Article 11 Calculation of the payments on account

If—

(a)

the total amount of tax, excluding the tax on goods imported from countries other than member States, which the taxable person was liable to pay by reference to the prescribed accounting periods the ends of which fell within any period of one year ending after the end of his reference period was less than 80 per cent. of the total amount of tax referred to in article 8 above, or

(b)

where such a period of one year has not ended, the Commissioners are satisfied that the total amount of tax, excluding the tax on goods imported from countries other than member States, which the taxable person will be liable to pay by reference to the prescribed accounting periods the ends of which fall within that year will be less than 80 per cent. of the total amount of tax referred to in that article,

then, with effect from the date of the written approval by the Commissioners of a written application by the taxable person to that effect, the lesser amount shall be substituted for the greater amount and the amount of each payment on account beginning with the first payment on account which falls to be made after the date of that approval shall, subject to article 10 above, equal one twelfth of that lesser amount.