4.—(1) This paragraph applies to a full-time or part-time contributor, who falls within paragraph 3(1)(b), and who, when his pensionable employment ended, was incapacitated and had not attained the age of 60.
(2) In this paragraph A and B have the same meanings as in paragraph 3.
(3) If the person was a full-time contributor, he is entitled to count as reckonable service—
(a)where the contribution period would not have expired before he attained the age of 60—
where
D is the period from the start of B to his 60th birthday; or
(b)in any other case, A.
(4) If the person was a part-time contributor, he is entitled to count as reckonable service—
(a)where the contribution period would not have expired before he attained the age of 60—
where—
D is the aggregate of—
(i)the period which he is entitled to count as reckonable service which arises from so much of the contribution period as had elapsed when the pensionable employment ended; and
(ii)the period from the date when the pensionable employment ended to his 60th birthday; or
(b)in any other case
where—
E is the period which he is entitled to count as reckonable service which arises from so much of the contribution period as had elapsed when the pensionable employment ended;
F is so much of the contribution period as elapsed when the pensionable employment ended.