Unless the refund is one described in ORS 323.320, interest shall be computed, allowed and paid upon any overpayment for the purchase of stamps at the rate established under ORS 305.220 for a period beginning 45 days after the due date for payment of the purchase for which the overpayment was made or on the date of the payment, whichever is later, and ending at the time the refund is made. No refund or credit shall be made of any interest imposed upon the claimant with respect to the amount being refunded or credited.
ORS 323.330