GST Value of Supply: 5 Additions Under Section 15 (2026)
Transaction value is only the starting point. Section 15(2) pushes five things back into the taxable value — other-law taxes, costs the buyer settled for you, incidental charges, late-payment interest, and price-linked subsidies other than Central or State Government ones — while Section 15(3) lets only two kinds of discount out. Here is what goes on the invoice, why the March 2026 post-sale discount amendment is not yet in force, and when Rules 27 to 31 take over from the price you agreed.