1. In the case of a fraudulent return or of neglect or refusal to make a return with respect to any tax under this chapter, there is no limitation on the period of time the director has to assess.

2. Where a statute or a rule promulgated by the director has exempted or excepted any person from the payment of tax under this chapter and is thereafter held by a final decision of the Missouri supreme court to be invalid, the director shall not be entitled to make an original or additional assessment of taxes which result from such court decision, nor shall the person be entitled to any refund or credit resulting from such court decision, for any period occurring prior to the date of the court’s mandate or the implementation of regulations interpreting such court decision, whichever is later.

3. In other cases, every notice of additional amount proposed to be assessed under this chapter shall be mailed to the person within three years after the return was filed or required to be filed.

4. (1) In those cases in which, within three years prior to June 12, 1990, a statute or a rule promulgated by the director has exempted or excepted any person from the payment of tax under this chapter and such statute or rule promulgated by the director is thereafter held by a final decision of the Missouri supreme court to be invalid, and such decision by the court has created significant claims for credits or refunds among substantial numbers of persons where quantifying such claims would reasonably require additional litigation or auditing by the state, or the amount which would be owed by such persons within the three-year period specified in subsection 3 of this section is not readily determinable with reasonable accuracy because of the lack of records or differing contractual relationships between the sellers and resellers, the director, or any person authorized in writing by him, shall offer to enter into an agreement with any person relating to the liability of such person in respect to the tax imposed by this chapter for any taxable period, which agreement shall contain the terms set out in subdivisions (2) through (5) of this subsection.

(2) The director shall accept as adequate consideration for an agreement the person’s agreement to:

(a) Waive all claims for refund or credit of sales or use taxes which claims result from such court decision for tax periods beginning prior to the later of the date of the court’s decision holding that the statute or rule promulgated by the director is invalid or the implementation of regulations interpreting that decision;

(b) Not initiate or intervene in as a party, for the two-year period following the date of the agreement, in the administrative hearing commission or any federal or state court, any cause of action attacking the constitutionality or general validity of taxes imposed upon the person by chapter 144; provided, however, that such agreement shall not prevent the person from initiating claims such as those based upon clerical or mathematical errors or double payment and claims based upon the application to the person of exceptions or exemptions provided for by rule or statute and provided further that if, for such two-year period, the person obtains a refund or credit as a result of a decision that the taxes imposed upon the person by chapter 144, are unconstitutional or of general invalidity, the person will take reasonable steps to return to identifiable purchasers from whom the person originally collected the tax under a written or oral contract the moneys refunded or credited and moneys not refunded or credited to identifiable purchasers, except those moneys resulting from vending machine sales, shall be returned to the state treasury less a ten percent fee to be retained by that person; and

(c) Waive the limitation period specified in subsection 3 of this section as to the three-year period preceding the date of the agreement in the event that the person breaches the provisions of this subdivision.

(3) The director shall agree not to seek an original or additional assessment for any period occurring prior to the later of the date of the court’s decision holding that the statute or rule promulgated by the director is invalid or the implementation of regulations interpreting that decision except as provided in subdivision (2).

(4) The case shall not be reopened as to matters agreed upon or the agreement modified by any officer, employee, or agent of this state.

(5) Such agreement shall be binding upon the personal representatives, successors, and assigns of the person.