1.    Whenever by any provisions of this chapter a refund is authorized, the commissioner shall certify the amount of the refund, the reason therefor, and the name of the payee to the office of management and budget, who shall thereupon draw a warrant on the general fund in the amount specified payable to the named payee. Interest of ten percent per annum must be allowed and paid upon any overpayment of tax from sixty days after the due date of the return or after the date the return was filed or after the date the tax due was fully paid, whichever comes later, to the date of the refund.

2.    If the tax commissioner disallows a claim for credit or refund, the tax commissioner shall notify the taxpayer accordingly. The decision of the tax commissioner to deny a claim is final and irrevocable thirty days after the date of notice unless within the thirty-day period the taxpayer files a written protest. A written protest must be filed under rules adopted by the tax commissioner under chapter 28-32.