Mr. Chair, commissioned officers cannot be sentenced to the punishment of detention. They can only be sentenced, in terms of custodial punishments, to the punishment of imprisonment.
In essence, the option of detention is a break that non-commissioned members get. There's a long, principled reason why, but the general theory is that if a commissioned officer commits an offence that is so great that he or she should be sentenced to a custodial sentence, it will be imprisonment, because it's likely that person isn't coming back to serve, whereas the purpose of a punishment of detention is essentially rehabilitative—to allow that person to correct the deficiency in discipline, to restore them to the standard of effectiveness they should be at, to come back in essence newly minted, and to hopefully carry on.
It's meant to be in essence a benefit for lower-ranked people, recognizing the fact that they don't have the same degree of responsibility that commissioned officers would have.