13. Whoever-(a) Keeps for use a motor vehicle without having paid the tax or additional tax in respect of such vehicle, or (b) delivers a declaration or additional declaration wherein the particulars required by or under this Act to be therein set forth are not fully and truly stated, shall be punishable with fine which may extend to one and a-half times, and, in the event of such person having been previously convicted of an offence under this Act or any rule made thereunder, with fine which any extend to twice the amount of the tax payable for the year for the motor vehicle in respect of which the offence is committed and the amount of any tax due shall also be recovered as if it were a fine.