Valuation of supply under GST: cost based or residual methods determine taxable value for ancillary services and canteen supply. Valuation under CGST offers a cost based approach (cost plus mark up or production cost) or a reasonable means approach; where earlier rules do not determine value, the residual method sets value by reference to amounts received or receivable. Suppliers of services may elect the residual rule. Advance rulings treated employee subsidised canteen deductions as taxable canteen supply with value to be fixed under these rules and disallowed input tax credit on related manpower supply services; another ruling applied the residual method equating value to the amount received for the supply.