Matching of credit notes: unmatched or duplicated reductions are added back to supplier output tax and attract interest. Matching requires alignment of a supplier's credit note details with the recipient's corresponding reduction in input tax credit in valid returns; matched claims are accepted and communicated. Discrepancies where supplier reductions exceed recipient declarations, and duplications, are communicated and the unresolved amounts are added to the supplier's output tax liability in the prescribed month. Suppliers bearing added amounts pay interest from the date of the original claim; if the recipient later declares the credit note within the permitted time, the supplier may reclaim the added amount and receive refunded interest credited to the electronic cash ledger, subject to a refund cap tied to interest paid by the recipient.