Assessee was a 100% export-oriented unit and engaged in the business of running a call centre and IT Enabled and Remote Processing Services. It filed return of income declaring loss and claimed exemption under section 10B.  Assessee stated that no loss was being carried forward as the assessee was 100% export-oriented unit and entitled to claim an exemption under Section 10B. However, later assessee filed a revised return of income demanding carry forward of losses by not claiming exemption under section 10B.  The Assessing Officer (AO) rejected the claim of carrying forward of loss as the revised return of income can be filed under Section 139(5) only to remove the omission and mistake and/or correct the arithmetical error. It cannot be filed for altogether a new claim. High court allowed the claim of the assessee. On appeal the Supreme Court held that   claim of exemption withdrawn in revised return filed after due date and loss claimed to be carried forward is held to be not permissible. The assessee was not entitled to the benefit under section 10B(8) of the Act on account of its failure to comply with the twin conditions as provided under section 10B(8) of the Act. Court also held that Chapter III and Chapter VI-A of the Act operate in different realms and the principles of Chapter III, which deals with “incomes which do not form a part of total income”, cannot be equated with the mechanism provided for deductions in Chapter VI-A, which deals with “deductions to be made in computing total income”. Therefore, rulings on the interpretation of Chapter VI-A will not be applicable while considering the claim under section 10B(8) of the Act. (AY.  2001-02)