Time of supply in HAM highway contracts follows continuous supply rules, with annuity interest included in taxable value. Time of supply under Hybrid Annuity Mode highway contracts is determined by treating construction and operation and maintenance as a single continuous supply of services. The contract cannot be split into separate construction and maintenance supplies based on staggered payments. If invoices are issued on or before the contractual due date or event completion date, the time of supply is the date of invoice or receipt of payment, whichever is earlier; otherwise, it is the date of provision of service or receipt of payment, whichever is earlier. Any interest component in the annuity is included in taxable value.