Section 19A(a) in The Kerala General Sales Tax Act, 1963
(a)if a dealer receives in any year any amount due to price variations, which would have been included in his turnover for any previous year if it had been received by him in that year, he shall within thirty days from the end of the year in which such amount is received, submit a return in the prescribed form to the assessing authority and thereupon the assessing authority shall proceed to assess the tax payable on such amount;
