z3ta 2.1 oversampling

As noted in another thread, a helpful forumite told me that I could lower my oversampling (whatever that is) to reduce the burden on my CPU, WHICH it does.
 
However, it seems to default on 2X.
When I change the value for realtime and playback, it stays there UNTIL I change to a different patch.
Then it jumps back to 2X... or sometimes 1X. 
 
Am I missing a "master" setting somewhere?