Time of supply of goods: earlier of invoice issuance or payment receipt determines tax liability timing. The time of supply of goods is the earlier of invoice issuance (or its last required date) and receipt of payment, with payment treated as the earlier of book entry or bank credit; a small excess received may be optionally deemed supplied at invoice date. For reverse-charge supplies the earliest of goods receipt, recorded payment or the date after thirty days from supplier's invoice determines time of supply, with voucher supplies and fallback rules (return filing date or tax payment date) specified; additions to value have time of supply when received.