Actually, what I've seen is the following: You're on duty for some reason, and you have to lock/unlock/safety check the buildings belonging to your unit. Then you have the option to go home and travel back to base to do the 21H00 check or to stay overnight (it all depends of the unit's standing orders). With some unit you may have a pager and be expected to be on the spot quickly to unlock a building for that Snco or Officer who has to work late, or to unlock a compound at 3 AM to let the boys on EX in to exchange a vehicle or something.
Please note that it all depends of the situation, unit, trade.
The Bottom line: Don't complain about gas or distance or anything like this or you'll hear "Listen ,you knew what you were doing when you moved, so STFU!".
I know guys myself who are living outside the boundaries and it's not bad ,they just bought a vehicle easy on gas...
Reference IRRP or other admin stuff, I've no idea...
Just my 2 cents...