S. 43B : Deduction only on actual payment-Rectification of mistakes-Gratuity amount incorrectly claimed under wrong schedule in return-Not reflected in tax audit report-Centralised Processing Centre disallowing claim under section 143(1)-Assessee filing revised tax audit report-Genuine claim could not be denied-CBDT Circular-Income of assessee should not be over-assessed-Legitimate deduction not to be denied merely because of a mistake made by assessee. [S. 143(1), 154]