1. In case of failure to file any return required under sections 143.011 to 143.996 on the date prescribed therefor (determined with regard to any extension of time for filing), unless it is shown that such failure is due to reasonable cause and not due to willful neglect, there shall be added to the amount required to be shown as tax on such return five percent of the amount of such tax if the failure is not for more than one month, with an additional five percent for each additional month or fraction thereof during which such failure continues, not exceeding twenty-five percent in the aggregate. For purposes of this section, the amount of tax required to be shown on the return shall be reduced by the amount of any part of the tax which is paid on or before the date prescribed for payment of the tax and by the amount of any credit against the tax which may be claimed upon the return.

2. In case of each failure to file a statement of payment to another person required under the authority of sections 143.011 to 143.996 including the duplicate statement of tax withheld on wages on the date prescribed therefor (determined with regard to any extension of time for filing), unless it is shown that such failure is due to reasonable cause and not to willful neglect, there shall be paid upon notice and demand by the director of revenue and in same manner as tax, by the person so failing to file a statement, a penalty of two dollars for each statement not so filed, but the total amount imposed on the delinquent person for all such failures during any calendar year shall not exceed one thousand dollars.