(1)If the amount of luxury tax payable under Section 5 in respect of any period is not paid by the stockist referred to in Section 7 by the date prescribed under that Section, such stockist shall pay a simple interest at the rate of three per centum for each month of default from the first day of such month next following the prescribed date to the last day of the month prior to the month in which such tax is fully paid or up to the month prior to the month of assessment under Section 9 in respect of such period, whichever is earlier, upon so much of the amount of luxury tax payable by him according to return where return is furnished, or according to such assessment where return is not furnished, as remains unpaid at the end of each such month of default.
