Iowa Code § 505.11

Whenever it appears to the satisfaction of the commissioner of insurance that, because of error, mistake, or erroneous interpretation of statute, a foreign or domestic insurance corporation has paid to the state of Iowa taxes, fines, penalties, or license fees in excess of the amount legally chargeable against it, the commissioner of insurance shall have power to refund to such corporation any such excess by applying the amount of the excess payment toward the payment of taxes, fines, penalties, or license fees already due or which may become due, until such excess payments have been fully refunded.