Section 9(2)(c) in Kerala Value Added Tax Rules, 2005
(c)in relation to Annual Maintenance Contract where the goods transferred in the execution of such contract is ascertainable from the accounts of the dealer be the turnover of such goods (which shall not exceed the total amount of the contract) calculated by adding the gross profit as per accounts to the purchase value of the goods and where the goods are not so ascertainable be fifty percent of the amount of the contract.