8. Where—
(a)a person was at any time employed in a single local government employment (“the first employment”),
(b)he becomes entitled to a benefit in relation to one of two or more concurrent local government employments (“the second employment”), and
(c)his remuneration in the first employment becomes material for the purpose of calculating that benefit,
that remuneration shall for that purpose be reduced to such amount as bears the same relation to it as the annual rate of remuneration of the second employment at the date when he ceased to hold that employment bears to the total of the annual rates of remuneration of all the concurrent employments at that date.