Additional tax payable in certain cases

(1) Where before the commencement of this Act tax in respect of a motor vehicle for the quarter, half year or year commencing on the first day of April, 1963, has been paid at the rates in force at the time of payment, the registered owner or person having possession or control of such motor vehicle shall be liable to pay, in addition, an amount equal to the difference between— (i) the tax calculated at the rate fixed under this Act for the period beginning with the date of commencement of this Act and ending with the quarter, half year or year as the case may be, and (ii) the tax calculated at the rate in force immediately before the commencement of this Act for the same period. (2) The amount payable under sub-section (1) shall be paid in such manner and within such time as may be prescribed.