Section 13 - Time of supply of services.

Time of supply of services determines when tax liability arises based on invoice, payment, recipient records, reverse charge, or vouchers.

The provision fixes Time of supply as the point when service tax liability arises, using the earliest of invoice issuance (if timely), payment receipt, service provision (if invoice delayed), or the recipient's books. It permits a supplier to treat certain excess receipts by invoice date. It defines payment receipt as earlier of book entry or bank credit, and sets tailored rules for reverse charge, vouchers, fallback mechanisms when timing is indeterminate, and for timing of value additions which is the date of receipt of such additions.