Where any purchaser, being a registered dealer, has been issued with a credit note or debit note in terms of sub-section (1) of section 17 or if he returns or rejects goods purchased, as a consequence of which, the input tax credit availed by him in any period in respect of which the purchase of goods relates, becomes less or excess, he shall compensate such less credit or excess credit by adjusting the amount of tax credit allowed to him in respect of the tax period in which the credit note or debit note has been issued or goods are returned subject to conditions as may be prescribed.