Matching of credit notes requires supplier reductions to align with recipient input tax returns or face additions and interest. Matching of credit notes requires suppliers' reductions in output tax liability to align with corresponding reductions in recipients' input tax credit declared in valid returns and to be checked for duplication. Matched claims are accepted and communicated; discrepancies where supplier reductions exceed recipient adjustments or where recipients fail to declare credit notes are communicated and, if not rectified timely, added to the supplier's output tax liability. Duplication findings are similarly added. Added amounts attract interest from the date of claim until addition; subsequent valid recipient declaration permits supplier adjustment and refund of interest to the electronic cash ledger, subject to limits.