Actually, officers can sell back leave. You can only sell back 60 days of leave in a career. This becomes a player when transitioning to the ANG/AFRC. When you do a month MPA tour, you accumulate 2.5 days of leave, which will automatically get sold back at the end of the tour. If you sold back all 60 days at the end of Active Duty, you're SOL, so they say.
I sold back 30 days at the end of AD and took the rest as terminal leave before joining the ANG.
Nowhere else are you going to ge