Process: 506/2015-T

Date: March 11, 2016

Tax Type: Selo

Source: Original CAAD Decision

Summary

CAAD Process 506/2015-T addresses a critical dispute regarding Stamp Tax (Imposto de Selo) under heading 28.1 of the General Table (TGIS) for high-value urban properties. A public company contested €26,136.60 in Stamp Tax assessments for 2014 on a Lisbon property constituted as vertical ownership with 13 independent units. The central legal question involves whether the tax threshold of €1,000,000 applies to the global property value or to each independent unit's VPT (taxpayer property value). The claimant argued that since no individual unit exceeded €1,000,000, no Stamp Tax was due, seeking reimbursement plus compensatory interest under article 43(1) of the General Tax Law. The Tax Authority defended that the total property value determines tax incidence, not individual unit values. Additionally, the Tax Authority raised a jurisdictional objection, arguing CAAD lacked competence to review payment installment notices rather than assessment acts themselves. The tribunal analyzed article 2 of RJAT regarding arbitral jurisdiction over tax assessments, examining whether collection notes constitute assessable acts under the legal framework. The case involved joinder of multiple related claims under articles 104 CPPT and 3 RJAT. This decision has significant implications for taxation of vertical property ownership structures and clarifies the scope of CAAD's jurisdiction over Stamp Tax collection procedures.

Full Decision

ARBITRAL DECISION

1. Report

On 28-07-2015, the public company A…, S.A., taxpayer number…, with registered office at Avenue…, no.…, …, …-… Lisbon, hereinafter referred to as the Claimant, submitted to the Centre for Administrative Arbitration (CAAD) a request for the constitution of an arbitral tribunal with a view to declaring illegal the acts of assessment of Stamp Tax in the total amount of 26,136.60 €, concerning the year 2014 and heading 28.1 of the General Table of Stamp Tax. Said assessments relate to the urban property located at Avenue…, no.… to …, Lisbon, registered in the urban property roll of the parish of … under article …, constituted as vertical property ownership and comprising thirteen divisions capable of independent use.

The Claimant alleges that the subjection to stamp tax is determined not by the global taxpayer property value (VPT) of the property, but by the VPT attributed to each of the floors or independently used divisions. And since none of the floors with independent use has a taxpayer property value (VPT) exceeding one million euros (1,000,000 €), Stamp Tax cannot be assessed or collected.

The Claimant finally requests the reimbursement of the tax improperly paid, plus compensatory interest, in accordance with article 43, no. 1 of the General Tax Law.

A sole arbitrator, Suzana Fernandes da Costa, was appointed on 13-10-2015.

In accordance with the provisions of article 11, no. 1, subparagraph c) of the RJAT, the singular arbitral tribunal was constituted on 28-10-2015.

The Tax and Customs Authority submitted its response on 27-11-2015, defending the maintenance of the tax acts in question, requesting the rejection of the claim, and alleging that the taxpayer property value relevant for purposes of tax incidence would be the total taxpayer property value of the urban property and not the taxpayer property value of each floor or division, even though they were capable of independent use.

The T.C.A. presented, in its response, a defense by way of exception, stating that the Arbitral Tribunal is materially incompetent to assess the legality of a payment installment of an act of assessment, which would not in itself constitute a tax act, noting that the Claimant contests exclusively the collection notes which constitute the first installment of the tax for the year 2014, relating to the property in question.

On 07-12-2015, the Claimant filed with the record a motion containing its response to the exception, accompanied by three documents.

On 10-12-2015, an order was issued scheduling the meeting provided for in article 18 of the RJAT, for 05-01-2016 at 16:15 hours.

At the meeting, the distinguished representative of the Claimant and the distinguished legal advisors representing the Director-General of the Tax and Customs Authority were present.

For its part, the Claimant's representative stated its position on the exception raised by the Respondent, in the sense that it was without merit.

The Respondent's representative declared that it maintained its position as stated in its response.

The arbitral tribunal decided to grant a period of 15 days for the Claimant and the Respondent, in that order, to present their written arguments. The arbitral tribunal further decided to set 11-03-2016 for the delivery of the arbitral decision. Finally, the Claimant was warned to, by that date, proceed with the payment of the subsequent arbitral fee, and to communicate such payment to the CAAD.

The Claimant filed its arguments as well as proof of the subsequent arbitral fee on 21-01-2016 and the Respondent presented its arguments on 04-02-2016.

The parties have legal personality and capacity and are legitimately entitled (articles 4 and 10, nos. 1 and 2 of the RJAT and article 1 of Order no. 112-A/2011 of 22 March).

The arbitral request is timely, in accordance with article 10, no. 1, subparagraph a) of Decree-Law no. 10/2011 of 20 January and article 102, no. 1, subparagraph a) of the Code of Tax Procedure and Process.

The proceeding is not subject to nullities and no preliminary questions were raised, except for the request for joinder of claims which shall be decided hereinafter.

The Claimant requested joinder of claims, alleging that "the merit of the claims submitted depends essentially on the assessment of the same factual circumstances and on the interpretation and application of the same rules of law."

In this case, joinder of claims is admissible, in accordance with articles 104 of the CPPT and 3 of the RJAT, and is therefore admitted.

2. On the exception of incompetence of the Arbitral Tribunal

The T.C.A. presented, in its response, a defense by way of exception, stating that "the Arbitral Tribunal is materially incompetent, in light of the provisions of article 2 of the RJAT, to assess the legality of a payment installment of an act of assessment, which is not in itself a tax act, there being no doubt whatsoever, given all the documents attached to it, that the Claimant contests exclusively the collection notes which constitute the 1st installment of the tax for the year 2014, relating to the property." And it transcribes parts of the decision in CAAD case no. 726/2014-T.

According to article 608 of the Code of Civil Procedure, the judgment addresses, in the first place, the procedural questions that may result in dismissal of the action, according to the order imposed by their logical precedence, and the judge must resolve all questions that the parties have submitted to their consideration, except those whose decision is foreclosed by the solution given to others.

Having the T.C.A. invoked the exception of incompetence of the Arbitral Tribunal to assess the arbitral request submitted by the Claimant, it is incumbent upon the Tribunal to rule on the same now.

In accordance with the provisions of article 2 of the RJAT, the jurisdiction of arbitral tribunals includes the declaration of illegality of acts of assessment of taxes, self-assessments, withholding at source and payments on account, as well as the declaration of illegality of acts fixing taxable matter when they do not give rise to the assessment of any tax, acts determining the taxable base and acts fixing taxpayer property values.

Let us examine the concept of assessment. According to José Casalta Nabais, in his work Tax Law, 3rd edition, Almedina 2015, page 318, "assessment in the broad sense, that is to say, as the totality of all operations intended to determine the amount of tax, comprises subjective assessment intended to determine or identify the taxpayer or tax debtor in the tax legal relationship, objective assessment through which the taxable or taxed matter of the tax is determined (and likewise, the rate to be applied, in the case of multiple rates)", while "assessment in the strict sense" is expressed as "the determination of the collection through the application of the rate to the taxable or taxed matter and any deductions from the collection".

Article 23, no. 7 of the Stamp Tax Code states that in the case of tax due under the situations provided for in heading no. 28 of the General Table, the tax is assessed annually, applying, with the necessary adaptations, the rules contained in the Property Tax Code. And article 113, no. 2 of the Property Tax Code states that assessment is effected in the months of February and March of the year following that to which it relates.

Thus, even though it may be paid in various installments, this fact does not mean that multiple assessments have occurred.

In the present case, the Claimant presents the arbitral request, requesting the "submission for consideration by the arbitral tribunal of the legality of the assessments of Stamp Tax (heading 28 of the General Table of Stamp Tax), identified under nos. 2015…, 2015…, 2015…, 2015…, 2015…, 2015…, 2015…, 2015…, 2015…, 2015…, 2015… and 2015…, concerning the year 2014, in the total amount of € 26,136.60".

Thus, taking into account the Claimant's petition and the Stamp Tax assessments attached by it, we understand that the Claimant intended, with its arbitral request, to request the annulment of the Stamp Tax assessments of the property in question, for the year 2014, in the total amount of 26,136.60 €, and not merely the first of the three installments of the said Stamp Tax.

Therefore, the exception of incompetence of the Arbitral Tribunal to rule on the claim is without merit, since it is not a question of assessing the legality of a payment installment of an act of assessment, but rather assessing the legality of an act of assessment of Stamp Tax.

3. Factual matter

3.1. Proven facts:

Having analyzed the documentary evidence produced and the position of the parties contained in the procedural documents, the following facts are considered proven and relevant to the decision of the case:

  • The Claimant was, in 2014, the owner of the urban property located at Avenue…, no.… to …, parish of…, municipality of Lisbon, registered in the urban property roll of said parish under no.…, and is constituted as full property ownership with thirteen divisions capable of independent use, as shown in the property deed attached with the arbitral request as document 13.

  • The Claimant was notified of the following Stamp Tax assessments for the year 2014, attached to the arbitral request as documents 1 to 12:

  • assessment no. 2015… in the amount of 1,804.10 €, relating to the 1st floor right of the aforementioned property, whose VPT is 180,410.00 €;

  • assessment no. 2015… in the amount of 1,949.80 €, relating to the 1st floor left of the aforementioned property, whose VPT is 194,980.00 €;

  • assessment no. 2015… in the amount of 1,824.10 €, relating to the 2nd floor right of the aforementioned property, whose VPT is 182,410.00 €;

  • assessment no. 2015… in the amount of 2,002.90 €, relating to the 2nd floor left of the aforementioned property, whose VPT is 200,290.00 €;

  • assessment no. 2015… in the amount of 1,824.10 €, relating to the 3rd floor right of the aforementioned property, whose VPT is 182,410.00 €;

  • assessment no. 2015… in the amount of 2,002.90 €, relating to the 3rd floor left of the aforementioned property, whose VPT is 200,290.00 €;

  • assessment no. 2015… in the amount of 1,813.50 €, relating to the 4th floor right of the aforementioned property, whose VPT is 181,350.00 €;

  • assessment no. 2015… in the amount of 1,991.30 €, relating to the 4th floor left of the aforementioned property, whose VPT is 199,130.00 €;

  • assessment no. 2015… in the amount of 3,550.40 €, relating to the 5th floor of the aforementioned property, whose VPT is 355,040.00 €;

  • assessment no. 2015… in the amount of 2,710.80 €, relating to the 6th floor of the aforementioned property, whose VPT is 271,080.00 €;

  • assessment no. 2015… in the amount of 2,142.50 €, relating to the 7th floor right of the aforementioned property, whose VPT is 214,250.00 €;

  • assessment no. 2015… in the amount of 2,520.20 €, relating to the 7th floor left of the aforementioned property, whose VPT is 252,020.00 €.

  • None of the floors or divisions with independent use has a taxpayer property value exceeding one million euros.

  • The Claimant proceeded with the payment of the first installment of the Stamp Tax assessments mentioned above, as evidenced by the proof attached with the arbitral request as document 14.

No other facts with relevance to the decision of the case were proven.

3.2. Substantiation of the proven factual matter:

With regard to the proven facts, the arbitrator's conviction was based on the documents attached to the record by the Claimant, namely the assessments and the property deed.

4. Legal matter:

4.1. Object and scope of the present proceeding

The question to be decided in the present case is whether heading 28.1 of the General Table of Stamp Tax (GTST), in the case of properties not constituted as horizontal property ownership, applies to the sum of the taxpayer property value attributed to the different parts or floors (global VPT), or rather to the taxpayer property value of each part of the property with independent economic use.

On this question, among others, the awards of the CAAD rendered in cases number 280/2013-T, 26/2014-T, 88/2014-T, 206/2014-T, 290/2014-T, 428/2014-T, 451/2014-T, 457/2014-T, 458/2014-T and 567/2014-T, 724/2014-T, 152/2015-T, 174/2015-T, 236/2015-T, 311/2015-T, 411/2015-T, 431/2015-T, 449/2015-T, 461/2015-T, 463/2015-T, 474/2015-T and award no. 047/15 of the Supreme Administrative Court (STA) have already ruled.

4.2. Question of the taxpayer property value relevant to the application of heading 28.1 of the GTST

According to the T.C.A., in a property in vertical ownership (or not constituted under horizontal property ownership regime) the criterion for determining the incidence of stamp tax is the global taxpayer property value of the floors and divisions intended for housing.

For the Claimant, on the other hand, the subjection to stamp tax contained in heading no. 28.1 of the GTST should be assessed not by the total value of the property but by the value attributed to each of the parts with independent use, according to their respective VPT.

Let us examine:

Law no. 55-A/2012, of 29 October, added heading 28 to the General Table of Stamp Tax (GTST), with the following wording:

"28 – Ownership, usufruct or right of superficies of urban properties whose taxpayer property value contained in the roll, in accordance with the Property Tax Code (CIMI), is equal to or greater than € 1,000,000 – on the taxpayer property value used for purposes of Property Tax:

28.1 – For property with residential use – 1% (…);

In the transitional provisions contained in article 6 of said Law no. 55-A/2012, the following rules were established:

c) The taxpayer property value to be used in the assessment of the tax corresponds to that resulting from the rules provided for in the Property Tax Code by reference to the year 2011; (…)

f) The applicable rates are as follows:

i) Properties with residential use assessed in accordance with the Property Tax Code: 0.5%;

ii) Properties with residential use not yet assessed in accordance with the Property Tax Code: 0.8%;"

Heading 28.1 GTST and the subparagraphs i) and ii) of paragraph f) of no. 1 of article 6 of Law no. 55-A/2012 contains a concept that is not used in any other tax legislation, which is "property with residential use."

For its part, article 67, no. 2 of the Stamp Tax Code, added by said Law, provides that "to matters not regulated in the present code relating to heading 28 of the General Table, the CIMI shall apply subsidiarily."

The rule of incidence refers to urban properties, whose concept is that which results from the provisions of article 2 of the CIMI, with the determination of the VPT subject to the terms of articles 38 et seq. of the same code.

In turn, article 6 of the CIMI indicates the different types of urban properties, and provides that "residential, commercial, industrial or service buildings are those licensed for such purpose or, in the absence of a license, that have as their normal destination each of these purposes." (see subparagraph a) of no. 1 of article 6 CIMI).

It must therefore be concluded that for the legislator it is irrelevant whether the property is in vertical ownership or in horizontal ownership, what matters is only the material truth underlying its existence as an urban property and its use.

Since the Stamp Tax Code (STC) defers to the Property Tax Code, we should consider that the registration in the roll of properties in vertical ownership, constituted by different parts, floors or divisions with independent use, follows the same registration rules as properties constituted as horizontal ownership.

From this it follows that the respective Property Tax, as well as Stamp Tax, are assessed individually in relation to each of the parts. For this reason, the legal criterion for defining the incidence of the new tax must be the same.

Thus it is concluded, as in award no. 50/2013-T of the CAAD and in award no. 047/15 of the STA, according to which "if the legal criterion imposes the issuance of individualized assessments for the autonomous parts of properties in vertical ownership, in the same manner as it establishes for properties in horizontal ownership, it clearly established the criterion, which must be unique and unequivocal, for the definition of the rule of incidence of heading 28.1 of the GTST".

It thus follows from the law that stamp tax under heading 28.1 of the GTST would only apply if any of the parts, floors or divisions with independent use had a VPT exceeding one million euros (1,000,000.00 €), which does not occur in the present case.

The criterion defended by the T.C.A., which takes into account the sum of the parts, with the argument that the property would not be constituted under horizontal property ownership regime, finds no legal support and is contrary to the criterion that results from the CIMI and that applies by reference, in the area of Stamp Tax.

Furthermore, the law itself expressly establishes, in the final part of heading 28 of the GTST, that Stamp Tax applying to urban properties of value equal to or greater than one million euros (1,000,000.00 €) shall be "on the taxpayer property value used for purposes of Property Tax."

In conclusion, the taxpayer property value relevant for purposes of the application of heading 28.1 of the GTST is the VPT of the part, floor or division with independent use with residential use, as concluded in award no. 047/15 of the STA.

In accordance with the interpretation endorsed above, the taxation of parts with independent use of value less than one million euros is not covered by the rule of incidence; therefore, their taxation violates the principle of equality, more specifically in its corollaries of taxpaying capacity and tax proportionality.

Regarding the principle of equality, see awards CAAD no. 50/2012-T and 218/2013-T, and awards of the Constitutional Court no. 142/04 and 187/2013.

We conclude, as in the award of the CAAD no. 218/2013-T, saying that "the assessment of Stamp Tax now under review manifestly violates the principle of tax equality provided for in article 13 of the CRP, because: i) it is based on a rule that treats taxpayers in identical situations in a very different manner, with the measure of the difference not being assessed by their real taxpaying capacity; ii) it is based on an arbitrary legal solution devoid of any rational foundation."

In the case at hand, the property in question is in vertical ownership and contains several floors and divisions with independent use intended for residential use, as was proven above. Given that none of the floors intended for residential use has a taxpayer property value equal to or greater than one million euros (1,000,000.00 €), as results from the documents attached to the record, it is concluded that the legal prerequisite for the incidence of Stamp Tax provided for in Heading 28 of the GTST has not been met.

Looking now at the ratio legis of the provision in question in heading 28.1 GTST and citing award CAAD no. 50/2013-T "the legislator, in introducing this legislative innovation, considered as the determining element of taxpaying capacity urban properties, with residential use, of high value (luxury), more precisely, of value equal to or greater than one million euros (1,000,000.00€), on which it proceeded to impose a special rate of stamp tax, intending to introduce a principle of taxation on wealth manifested in the ownership, usufruct or right of superficies of urban properties of luxury with residential use. For this reason, the criterion was the application of the new rate to urban properties with residential use, whose VPT is equal to or greater than one million euros (1,000,000.00 €). Clearly the legislator understood that this value, when attributed to a dwelling (house, autonomous fraction or floor with independent use) expresses a taxpaying capacity above the average and, as such, capable of determining a special contribution to ensure fair distribution of the tax burden." Whereas when applied to a part or fraction not exceeding said value of one million euros, the rule of incidence is not met.

The principle of tax equality requires that what is equal be treated fiscally in an equal manner and what is different be treated differently. However, there is no justification for differentiated treatment of fractions or parts of a property merely because it is already in horizontal property ownership, provided the fractions or parts have independent use.

As stated in award CAAD of case no. 218/2013-T, "The principle of tax equality is based on the general principle of equality provided for in article 13 of the CRP, from which results the principle of taxpaying capacity which, by constitutional imperative, is the prerequisite and criterion of taxation."

Professor Casalta Nabais asserts that the principle of tax equality has inherent above all "the idea of generality or universality, under which all citizens are subject to the fulfillment of the duty to pay taxes, and of uniformity, requiring that such duty be assessed by the same criterion — the criterion of taxpaying capacity. This thus implies equal tax for those with equal taxpaying capacity (horizontal equality) and different tax (in qualitative or quantitative terms) for those with different taxpaying capacity in proportion to this difference (vertical equality)" (Casalta Nabais, Tax Law, 5th edition, Coimbra, 2009, pp. 151-152).

In award CAAD of case no. 50/2013-T it can be read that "the tax legislator cannot treat equal situations differently. However, if the property were in horizontal property ownership regime, none of its residential fractions would be subject to incidence of the new tax."

Thus, and in line with the jurisprudence of the TC and CAAD, we conclude for the violation of the principle of tax equality and taxpaying capacity and, as such, for the merit of the claim.

5. On compensatory interest

The Claimant requested the condemnation of the T.C.A. to return the improperly paid tax, plus compensatory interest.

Article 43, no. 1 of the GTL establishes that "compensatory interest is due when it is determined, in a gracious complaint or judicial challenge, that there was error attributable to the services resulting in payment of the tax debt in an amount greater than that legally due".

In the case at hand, the error affecting the Stamp Tax assessments is attributable to the Tax and Customs Authority which performed the assessment acts on its own initiative, therefore the Claimant is entitled to compensatory interest from the date of payment of each of the amounts until reimbursement, at the legal supplementary rate, in accordance with articles 43, nos. 1 and 4, and 35, no. 10, of the GTL, article 559 of the Civil Code and Order no. 291/2003, of 8 April.

As results from said article 43, no. 1 of the GTL, the right to compensatory interest depends on the payment of tax debt in an undue amount.

Being affected by illegality, the Stamp Tax assessments give rise to compensatory interest from the date of payment until full reimbursement by the T.C.A., in accordance with articles 43 of the GTL and 61, no. 2 of the CPPT.

6. Decision

In view of the above, it is determined:

a) to judge the exception of incompetence of the Arbitral Tribunal without merit;

b) to judge entirely with merit the claim formulated by the Claimant in the present tax arbitral proceeding, regarding the illegality of the Stamp Tax assessments, concerning the year 2014, no. 2015… in the amount of 1,804.10 €, no. 2015… in the amount of 1,949.80 €, no. 2015… in the amount of 1,824.10 €, no. 2015… in the amount of 2,002.90 €, no. 2015… in the amount of 1,824.10 €, no. 2015… in the amount of 2,002.90 €, no. 2015… in the amount of 1,813.50 €, no. 2015… in the amount of 1,991.30 €, no. 2015… in the amount of 3,550.40 €, no. 2015… in the amount of 2,710.80 €, no. 2015… in the amount of 2,142.50 €, no. 2015… in the amount of 2,520.20 €.

c) to judge with merit the claim for condemnation of the Tax and Customs Authority to reimburse the Claimant the amount of the improperly paid tax, plus compensatory interest in accordance with the law, from the date such payment was made until the date of full reimbursement thereof.

7. Value of the proceeding:

In accordance with the provisions of article 306, no. 2, of the CPC and 97-A, no. 1, subparagraph a) of the CPPT and 3, no. 2 of the Regulation of Court Costs in Tax Arbitration Proceedings, the value of the action is fixed at 26,136.60 €.

8. Court costs:

In accordance with article 22, no. 4, of the RJAT, and Table I attached to the Regulation of Court Costs in Tax Arbitration Proceedings, the amount of court costs is fixed at 1,530.00 €, due by the Tax and Customs Authority.

Notify.

Lisbon, 11 March 2016.

Text drawn up by computer, in accordance with article 138, no. 5 of the Code of Civil Procedure (CPC), applicable by reference to article 29, no. 1, subparagraph e) of the Tax Arbitration Regime, revised by me.

The sole arbitrator

Suzana Fernandes da Costa

Frequently Asked Questions

Automatically Created

Is Stamp Tax under verba 28.1 TGIS calculated on the total property value or on each independent unit's VPT?
The core dispute concerns whether Stamp Tax under heading 28.1 TGIS applies to the aggregate property value or individual unit values in vertical ownership. The claimant argued taxation depends on each independent unit's VPT, while the Tax Authority maintained the global property VPT determines tax incidence. Since the decision excerpt is incomplete, the final ruling on this interpretation is not provided, but the case establishes this as a critical legal question for properties structured as vertical ownership.
Can a building in vertical ownership with units each valued under €1,000,000 be subject to Stamp Tax under verba 28.1?
According to the claimant's position, buildings in vertical ownership where each independent unit has a VPT below €1,000,000 should not be subject to Stamp Tax under heading 28.1, regardless of the total property value. However, the Tax Authority argues that the €1,000,000 threshold applies to the total property VPT, not individual units. This dispute highlights the importance of property structuring for tax purposes and the interpretation of heading 28.1 TGIS in relation to vertical property ownership.
How can taxpayers challenge Stamp Tax assessments on high-value urban properties in Portugal?
Taxpayers can challenge Stamp Tax assessments on high-value urban properties through CAAD (Centro de Arbitragem Administrativa) under article 10(1)(a) of Decree-Law 10/2011 and article 102(1)(a) of the Tax Procedure Code. The request must be filed within the legal timeframe. Claimants should identify the specific assessment acts contested, present legal grounds for illegality, and may request joinder of related claims under articles 104 CPPT and 3 RJAT when multiple assessments involve the same factual and legal circumstances.
Are property owners entitled to a refund and compensatory interest if Stamp Tax was unlawfully charged?
Yes, under article 43(1) of the General Tax Law, property owners are entitled to reimbursement of unlawfully charged Stamp Tax plus compensatory interest (juros indemnizatórios). In Process 506/2015-T, the claimant specifically requested both the tax refund of €26,136.60 and compensatory interest. The entitlement arises when tax assessments are declared illegal, whether due to incorrect legal interpretation, improper calculation basis, or other grounds establishing the tax was improperly collected.
Does CAAD have jurisdiction to review Stamp Tax collection notices as opposed to liquidation acts?
The Tax Authority raised a jurisdictional exception arguing CAAD lacks material competence to review payment installments (collection notes) as opposed to assessment acts. However, article 2 RJAT grants arbitral tribunals jurisdiction over acts of tax assessment. The tribunal analyzed whether collection notes constitute independent acts or merely reflect the underlying assessment. Following article 23(7) of the Stamp Tax Code and article 113(2) of the Property Tax Code, Stamp Tax is assessed annually even if paid in installments, suggesting the assessment act itself—not individual payment notices—is the proper object of review.