Section 353(2) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(2)Officers who are permitted to undergo a further voluntary specialist training or temporary service as specified in Part B of this Section before the expiry of their exemption from biennial obligatory training, shall be allowed, on completion of such voluntary training or service, either the balance of the period of exemption to their credit or the exemption they will gain as a result of the further voluntary training or service, according to the officers' choice.