Time of supply in HAM contracts: invoice date or payment receipt, whichever is earlier, subject to invoicing timelines. HAM concession agreements are single continuous supplies covering construction and O&M; time of supply is the invoice date or receipt of payment, whichever is earlier, where the invoice is issued on or before the contract specified due date/event; if invoice is not issued timely, time of supply is the date of provision of service or receipt of payment, whichever is earlier. Interest components in installments/annuities are includible in the taxable value under section 15(2)(d).