(a) Interest shall be allowed and paid on an overpayment of a tax under this title at the rate and in the manner provided in AS 43.05.225(1).
(b) Interest shall be allowed and paid as follows:
(1) in the case of a credit, from the date of the overpayment to the due date of the amount against which the credit is taken;
(2) in the case of a refund, from the date of the overpayment to a date, as determined by the department, preceding the date of the refund check by not more than 30 days, whether or not the refund check is accepted by the taxpayer after tender of the check to the taxpayer; the acceptance of the refund check does not affect the right of the taxpayer to claim an additional overpayment and interest on the overpayment.
(c) If an overpayment of a tax imposed by this title is refunded within 90 days after the last date prescribed for filing the return of the tax, determined without regard to an extension of time for filing the return, or if the return is filed after the last filing date and the overpayment is refunded within 90 days after the date the return is filed, interest may not be allowed under (a) of this section on that overpayment.