Matching of claim of reduction in output tax liability requires electronic reconciliation of credit note details and return acceptance. Rule 73, now omitted, required matching of claims reducing output tax liability by reconciling supplier and recipient GSTINs, credit note number and date, and tax amount against returns after the due date; extensions of matching deadlines were permitted where return filing timelines were extended and the Commissioner could further extend matching dates. A credit note accepted by the recipient without amendment was treated as matched if the recipient filed a valid return, and a reduction claim was matched where post-reduction output tax liability equalled or exceeded the recipient's admitted reduction in input tax credit in a valid return.