Matching of credit notes triggers adjustment of supplier output tax liability and communication of discrepancies for correction. The provision requires prescribed matching of supplier credit note details with the recipient's reduction in input tax credit to accept reductions and detect duplication. Discrepancies where supplier reductions exceed recipient declarations, or undeclared credit notes, are communicated and, if unrectified within the prescribed return period, added to the supplier's output tax liability in the succeeding return. Duplication additions are restored in the supplier's return when communicated. Suppliers whose liabilities are increased under these rules pay interest from the date of the original claim until addition; interest may be refunded by electronic credit if the recipient later declares the credit note, limited to the interest the recipient paid.