11In computing for the purposes of Schedule 2 to the [1975 c. 14.] Social Security Act 1975 the amount of the profits or gains of a trade in respect of which Class 4 contributions are payable—
(a)deductions or additions shall be made under paragraph 2 of that Schedule for any relief or charge under this Part of this Schedule which falls to be made in charging profits or gains to income tax under Case I of Schedule D ; and
(b)paragraphs 8 and 9 above shall be included among the relief provisions to which paragraph 3(1) of that Schedule applies.