Interest on late payment of TDS u/s 194q - calculated from date of purchase or payment?

This discussion addresses the calculation of interest on late TDS payments under Section 194Q. The core question is whether interest accrues from the date of purchase or the date of payment. While one user suggests departmental clarification points to the payment date, others argue it should be from the purchase date, citing the principle that TDS is deductible on the earlier of the two dates.