Section 9(5) in Kerala Value Added Tax Rules, 2005
(5)Amounts claimed by a dealer to be not includible in his total turnover, as representing discount allowed in accordance with the provisions of clause (ii) of Explanation III to clause (lii) of section 2 shall be that allowed in respect of sales effected during the period to which the return relates and is allowed in accordance with the regular practice in the trade. Where a dealer has claimed any amount as discount during a return period, he shall not revise the claim subsequently so as to enhance the amount of discount relating to such return period.
