I have the same issue and I'm using SDK 1.0.12 on Android 5.1.
I set RegionExitExpiration to 1s, but it seems, that it set to 20s.
with 0.16.0 all work fine, but not in 1.0.12.
I also tried to set it to 60s, but it's always 20s.
Is there an older version (no .0.16.0), where setRegionExitExpiration works?