Where any purchaser, being a registered dealer, has been issued with a credit note or debit note in terms of section 23, or where he returns or rejects goods purchased, as a consequence of which the input tax credit, availed by him for any period to which the purchase of goods relates, becomes less or excess, he shall make due adjustment of the amount of such less credit or excess 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.

Provided that no such adjustment shall be allowed in respect of such tax where any credit note has been issued as a consequence of cash discount or sale incentive by any registered dealer to another registered dealer after tax invoIce is issued.