Hey Robert.

My suggest is select distinct profiles for each machine, one with Beta testing selected and other without.

For example:

Put one machine working under your performance choices on your DEFAULT profile (just take a look at your DEVICE MANAGER option at left of your MY GRID page).

Put your other machine under another profile (could be WORK, SCHOOL or HOME dosen't matter, once you will choose what you desire) with same or distinct performance characteristics, but without selection for Beta testing.

Hope helped you. Good crunch.

edit:
PS: sorry Robert. don't appear before for me any post answer your one, including the post with the suggestion of the CA above. Despite of my suggest be for sure right for you, both suggestion are the same. Up to you.