Matching of credit notes ensures supplier reductions in output tax are verified, adjusted, and subject to reversal and interest. Credit note details supplied by a supplier must be matched with the recipient's reduction in input tax claims and checked for duplication; matched reductions are accepted and communicated. Discrepancies where supplier reductions exceed recipient declarations, or undeclared credit notes, are communicated and, if not rectified within the prescribed period, added to the supplier's output tax liability in the succeeding return. Duplicated reductions are also added back. Amounts so added attract interest until addition; subsequent valid declaration by the recipient permits the supplier to reclaim the amount and obtain an interest refund credited to the electronic cash ledger, subject to the cap of interest actually paid by the recipient.