Refunds of overpayment of tax. Interest.

(2) On or before the sixtieth day after the mailing of the proposed disallowance, the claimant may file with the commissioner a written protest against the proposed disallowance in which the claimant sets forth the grounds on which the protest is based. If a protest is filed, the commissioner shall reconsider the proposed disallowance and, if the claimant has so requested, may grant or deny the claimant or the claimant's authorized representatives an oral hearing. (3) The commissioner shall mail notice of his determination to the claimant, which notice shall set forth briefly the commissioner's findings of fact and the basis of decision in each case decided in whole or in part adversely to the claimant. (4) The action of the commissioner on the claimant's protest shall be final upon the expiration of one month from the date on which he mails notice of his action to the claimant unless within such period the claimant seeks judicial review of the commissioner's determination pursuant to section 12-597 . (b) (1) To any refund granted as a result of overpayments of any taxes imposed under section 12-587 , except refunds due because of any intentional overpayment, there shall be added interest at the rate of two-thirds of one per cent for each month or fraction of a month, as provided in subdivisions (2) and (3) of this subsection. (2) In case of such overpayment pursuant to a tax return, no interest shall be allowed or paid under this subsection on such overpayment for any month or fraction thereof prior to (A) the ninety-first day after the last day prescribed for filing the tax return associated with such overpayment, or (B) the ninety-first day after the date such return was filed, whichever is later. (3) In case of such overpayment pursuant to an amended tax return, no interest shall be allowed or paid under this subsection on such overpayment for any month or fraction thereof prior to the ninety-first day after the date such amended tax return was filed.