(1) The computation of the taxes as provided in Chapter 77, article 9, shall be made on forms furnished by the Department of Insurance and shall be forwarded to the department together with a sworn statement by an appropriate fiscal officer of the company attesting the accuracy of the tax computation. The department shall furnish such forms to the companies together with any information relative to the taxes as may be needful or desirable. Upon receipt of the tax payment, the director shall audit and examine the computations and satisfy himself or herself that the taxes have been properly paid in conformity with Chapter 77, article 9.

(2) Commencing with taxes imposed for 1985 or any subsequent year, whenever it appears to the satisfaction of the director that, because of a mistake of fact, error in calculation, or erroneous interpretation of a statute not pertaining to the statute's constitutionality, any tax has been erroneously paid to the director, he or she shall have the authority to refund or credit the amount of such erroneous overpayment. The refund or credit may be made by applying such amount towards the payment of other similar taxes already due or which may become due until such overpayment has been fully reimbursed. A claim for refund or credit of an overpayment of a tax caused by a mistake of fact, error in calculation, or erroneous interpretation of a statute not pertaining to the statute's constitutionality shall be filed by the taxpayer within one year from the date the overpayment was made or such claim shall be forever barred.