Matching of credit notes: unmatched or duplicated reductions are added back to supplier output tax, with interest and reclaim rules. Credit notes furnished by a supplier must be matched with corresponding reductions in the recipient's input tax credit in valid returns; matched reductions are accepted and communicated. If the supplier's reduction exceeds the recipient's declared reduction or the recipient fails to declare the credit note, the discrepancy is communicated and, if not rectified within the prescribed period, the amount is added to the supplier's output tax liability. Duplication of claims similarly results in addition to the supplier's liability. Added amounts attract interest until reversal, and interest paid may be refunded to the supplier via the electronic cash ledger if the recipient later declares the credit note.