(1) Subject to this section, a detainee who is serving a period of detention of not less than 28 days is entitled to a remission of one-quarter of the period of detention.
(2) If the remission of a period of detention would, apart from this subsection, reduce the period of detention to less than 24 days, the period of detention is to be remitted to a period of 24 days.
(3) If a custodial punishment is imposed on a detainee, the period of remission to which the detainee would, apart from this subsection, be entitled, must be reduced:
(a) for each day of the punishment of segregated confinement served by the detainee--by 3 days; or
(b) for each day of the punishment of confinement to a cell served by the detainee--by 2 days; or
(c) for each day of the punishment of extra drill served by the detainee--by 1 day; or
(d) for continuous or discontinuous periods of the punishment of restriction of custodial privileges which in the aggregate amount to more than 7 days--by 1 day for each such period of not less than 7 days.
(4) If a punishment of a period of detention is imposed on a detainee in respect of an offence committed during a period of detention, the detainee is not entitled to remission in respect of the latter period of detention.