Claim for credit or refund

In all cases of overpayment, duplicate payment, or payment made in error, the commissioner may issue a certificate stating therein the facts and the amount of the refund to which the taxpayer may be entitled. Upon presentation of the certificate to the office of management and budget, a warrant shall be issued to the taxpayer for the purpose of refunding any overpayment, duplicate payment, or payment made in error out of the unapportioned gross production tax in the state treasury and a pro rata share thereof must be charged against the county entitled to share in the tax. Interest arising from refunds of overpayments, duplicate payments, and erroneous payments must be allowed and paid at the rate of ten percent per annum and accrues for payment from sixty days after the due date of the return or after the return was filed or after the tax was fully paid, whichever comes later.
A taxpayer may file a claim for credit or refund of an overpayment of tax within three years of the due date of the return or three years after the return was filed. However, if there is a change in tax liability on any return by an amount in excess of twenty-five percent of the amount of tax liability reported on a return, a claim for refund of tax may be filed within six years after the due date of the return or six years after the return was filed, whichever period expires last.