Section 15th(6)(d) in The Navy (Pay And Allowances) Regulations, 1966
(d)When the period of one month prescribed under sub-regulation (2) of regulation 240 is extended by the sanctioning authority, the penal rate shall be charged with effect from the date following that on which the extended period expires.(dd)[ the penal rate of interest shall be the compound rate of interest and it would as merged with the principal at monthly intervals for the purpose of calculation of future rate of interest for the subsequent periods.] [Inserted by S.R.O. 9-E, dated 19th March, 1974]