Notwithstanding anything contained in this Act, if in respect of any supply the Federal Government is satisfied that inadvertently and as a general practice:-

(a) tax has not been charged in any area on any supply which was otherwise taxable, or according to the said practice the amount charged was less than the amount that should have actually been charged;

(b) the registered person did not recover any tax prior to the date it was discovered that the supply was liable to tax; and

(c) the registered person started paying the tax from the date when it was found that the supply was chargeable to tax;

It may, by a notification in the official Gazette, direct that the tax not levied or short levied as a result of that inadvertent practice, shall not be required to be paid for the period prior to the discovery of such inadvertent practice.