64A. In contracts of sale, amount of increased or deceased to tax to be added or deducted.-
(1) Unless a different intention appears from the terms of the contract, in the event of any tax of the nature described in sub-section (2) 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 stipulations as to the payment of tax where tax was not chargeable at the time of the making of the contract, or for the sale or purchase of such good tax- paid where tax was chargeable at that time.-
(a) if such imposition or increase so takes effect that the tax or increased tax, as the case may be, or any part of such 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 tax or increase of tax, and he shall be entitled to be paid and to sue for and recover such addition, and
(b) if such decrease or remission so takes effect that the decreased tax only, or no tax, as the case may be, is paid or is payable, the buyer made deduct so much from the contract price as will be equivalent to the decrease of tax or remitted tax, and he shall not be liable to pay, or be sued for, or in respect of, such deduction.
(2) The provisions of sub-section (1) apply to the following taxes, namely:-
(a) any duty of customs or excise on goods.
(b) any tax on the sale or purchase of goods.