11.—(1) Subject to the approval of the compensating authority, the deciding authority, ascertained from the first and second columns of the table in Part I of Schedule 1, may, within 6 months after the material date, credit an eligible teacher (including an eligible teacher who has since died) with a period of service not exceeding the shortest of—
(a)the period by which his effective service falls short of 40 years;
(b)the period beginning on the day following the material date and ending with his 65th birthday, less, where paragraph 1 of Part 3 of Schedule 1 applies, any period required by paragraph 2 of that Part to be deducted;
(c)the length of his effective service; and
(d)the period specified in Part 2 of Schedule 1.
(2) An eligible teacher’s effective service comprises—
(a)any period which he is entitled to count as reckonable service; and
(b)if his former employment was not pensionable employment, any period which he would have been entitled so to count if it had been.