In this connection, a reference was made to section 64 A of the , (substituted for the original section 64 A by the Sale of Goods (Amendment) Act, 1963, under which unless a different intention appears from the terms of the contract, in the event of any duty of customs or excise on goods or any tax on the sale or purchase of goods being imposed, increased, decreased or remitted in respect of any goods after the making of any contract for the sale or purchase of such goods, without stipulation as to the payment of such duty or tax where duty or tax was not chargeable at the time of the making of the contract, or for the sale or purchase of such goods duty paid or tax paid where duty or tax was chargeable at that time, if such imposition or increase so takes effect that the duty or tax or increased duty or tax, as the case may be, or any part of such duty or tax is paid or is payable, the seller may add so much to the contract price as will be equivalent to the amount paid or payable in respect of such duty or tax or increase of duty or tax, and is to be entitled to be paid and to sue for and recover such addition, and if 878 such decrease or remission so takes effect that the decreased duty or tax only, or no duty or tax, as the case may be, is paid or is payable, the buyer may deduct so much from the contract price as will be equivalent to the decrease of duty or tax or remitted duty or tax, and is not to be liable to pay or be sued for in respect of such deduction.