Input tax credit matching may trigger reversal and added output liability if supplier fails to declare details. Matching of claimed input tax credit against supplier returns, import tax payment, and duplicate claims is required; matched credits are accepted and communications prescribed. Unrectified discrepancies are added to the recipient's output tax liability in the succeeding month; duplication-based excesses are added in the month communicated. Recipient may reduce such additions if the supplier timely declares the invoice; interest runs on added amounts at the rate in section 50 until additions are made, with refund of interest to the recipient limited to interest paid by the supplier when reductions are accepted.