Interest shall be computed, allowed, and paid upon any overpayment for the purchase of stamps or meter register settings at the modified adjusted rate per month established pursuant to Section 6591.5, from the 26th day of the calendar month following the period during which the overpayment was made. In addition, a refund or credit shall be made of any interest imposed upon the claimant with respect to the amount being refunded or credited.
The interest shall be paid as follows:
Ca. Rev. and Tax. Code § 30179