68. Ongoing contracts

 (1) Where a contract or an agreement was concluded between two or more parties before the commencement of the Act and no provision for tax under the Act was made in the contract, the selling dealer shall pay tax due on any sale liable to tax made under such contract after the commencement of the Act.

(2) Where a contract is concluded after the commencement of the Act, and no provision relating to tax was made in the contract, the contract price shall be deemed to include tax due under the Act and the selling dealer shall account for the tax due.