(1) Where a supply of goods is made under a lay-by agreement‚ in that case-

(a) the output tax on such supply shall become payable when payments for such supply are made and, in each tax period, taxes shall be assessed and paid at the time of payment of the price; and

(b) the amount of assessed output tax in each tax period shall be the tax-fraction of the payments made in that period.

(2) Where supply of any goods is made under a lay-by agreement‚ separate tax invoices shall be required to be issued against payment of each instalment.