Time of supply for HAM road services: invoice date or payment receipt determines tax liability for construction and O&M. For HAM contracts treated as a single continuous supply covering construction and O&M, the time of supply is the earlier of invoice date or receipt of payment where invoices are issued on or before the contract-specified due date or event-completion date. If invoices are not issued by that date, the time of supply is the earlier of the date of provision of the service (which may be the contract due date) or receipt of payment. Interest included in installments/annuities is includible in the taxable value.