I think you meant "personnel" guru, not one that was soley for your reference.
That aside, I've encountered this several times in the USAF Reserve. I
have been allowed to take leave my last two days of duty (although I was on 32-34 days of orders); and a half day was sold-back (when a fraction applied). I'm not sure which service you fly the Herc in. This may be USAF or even unit-specific.
I don't believe you can "save" leave until your next 30-day order or deployment, which means it is "use it or cash it."