In default of such payment the whole of the amount then remaining due shall become recoverable in accordance with sections 16 and 16 A. x x x x x x (2) If the tax or any other amount due under this Act is not paid by the dealer or any other person, by whom it is payable, within the period specified in demand notice, the dealer or such other person shall be liable to pay interest on the tax or other amount from the date it was payable to the date of actual payment at the following rates (a) If the default is for a period of not exceeding three months at 1% per month; (b) If the default is for a period exceeding three months but less than six months at 2% per month; (c) If the default is for a period exceeding six months at 3% per month: Provided that where, as a result of an order under Sections 11, 12, 24 or an order of the Court, the amount of tax or other sum on which interest was payable under this sub section has been reduced, the interest shall be reduced accordingly and excess interest paid, if any, shall be refunded.