2.—(1) This paragraph applies where a lump sum equal to the retirement lump sum that would otherwise have been receivable is paid under paragraph 6 or 8 of Schedule 4.
(2) Where this paragraph applies, the person is entitled to count as reckonable service—
(a)the period he would have been entitled to count under paragraph 1 if the lump sum had not been paid, and
(b)a period of
where—
A is the retirement lump sum,
B is the lump sum that would have been payable under paragraph 5 of Schedule 4,
C is so much of the past period as he is not entitled to count under (a) above, and
D is his average salary.