I have a need for this also - but unfortunately I also need centering to be accurate in the first place or I can't use it.
I'm not sure how many people are doing automated imaging - especially unattended - with OAG and long focal length. There is a fundamental problem that if an adjacent guidestar is pulled into the scene by slight movement - it could be grabbed and result in an offset.
This could be fixed by doing a plate solve after the autofocus and confirming it is still within X arc-seconds of the target - and if not trigger a re-center.
This is obviously added complexity - but I think it is needed for automated oag runs. And it does require accurate centering.
Frank