Time of supply on tax rate change follows invoice and payment timing rules for goods and services. Determination of time of supply on a change in rate of tax follows special rules based on whether the supply occurs before or after the rate change, and on the timing of invoice issuance and payment receipt. The provision applies the earlier date of payment or invoice in specified cases, and deems receipt of payment to be the date of bank credit if credit occurs after four working days from the rate change. For this purpose, receipt of payment means the earlier of entry in the supplier's books or credit to the supplier's bank account.