(1) Subject to subsection (2), a detention order commences—
(a) if the offender is serving a custodial sentence when the detention order is made, on the day on which the offender completes the custodial sentence or any consecutive or concurrent custodial sentence, whichever is later; or
(b) if the offender is remanded in custody when the detention order is made, on the day on which the offender is released from custody; or
(c) if the offender is in immigration detention when the detention order is made, on the day on which the offender is released from immigration detention; or
(d) in any other case, on the date specified in the detention order.
(2) A detention order that has been renewed commences on the date specified in the renewed detention order.