Deduction restriction: claiming chapter deductions for specified business profits bars any additional special-deduction for that business. Where a deduction under any provision of the Chapter headed 'C. Deductions in respect of certain incomes' is claimed and allowed in respect of profits of a specified business, no deduction shall be allowed under the provisions of the special investment allowance regime in relation to such specified business for the same or any other assessment year; the amendment is prospective and applies from the stated operative date to the relevant assessment year and subsequent years.