4(1)Where during a person's period of deferment there are one or more increases (other than any made by such an order as is mentioned in paragraph 3(4) above) in the weekly rate of graduated retirement benefit which would have been payable to him during that period if he had not deferred his retirement from regular employment or made an election by virtue of section 30(3) of the Act, the total amount of increment for the period of deferment shall be—N.I.
(a)1/7th per cent., for each incremental period in the period of deferment, of the weekly rate of the graduated retirement benefit to which he would have been entitled immediately after his retirement if he had retired on attaining pensionable age; plus
(b)in respect of each such increase, 1/7th per cent. of its weekly rate for each incremental period in the period beginning with the day on which that increase occurred and ending with the day before that of the person's retirement.
(2)Where one or more orders have come into force under section 120 of the Act during the period of deferment the weekly rates mentioned in sub-paragraph (1) above shall be determined as if the order or orders had come into force before the beginning of the period of deferment.