Matching of credit notes links supplier output reductions to recipient returns, with additions and interest for unresolved discrepancies. Matching requires reconciliation between a supplier's reduction in output tax liability and the recipient's reduction in input tax credit in valid returns; matching accepts and communicates supplier claims. Discrepancies where supplier reductions exceed recipient declarations, or undeclared credit notes, and duplications are communicated, and unrectified or duplicated amounts are added to the supplier's output tax liability in the prescribed return periods. Suppliers may reclaim added amounts if recipients later declare within the prescribed time; interest is payable by the supplier on added amounts and refunded up to the interest actually paid by the recipient, while contraventions attract addition and interest.