S. 40(a)(ia): Amounts not deductible-Deduction at source]-Payment of sales commission and cash incentives to retailers-the assessee filed various evidences including confirmation from the parties to prove the genuineness of said expenditure, adverse inference cannot be drawn merely because the notices issued under s. 133(6) were returned unserved by the postal authorities.[S.37(1), 133(6), 194H]