Now that is news to me on that one! What are the specifics of having to do so? I helped a local carver do the CT upgrade on his machine (A) that does not have the A907 upgrade and he has put on over 300 hours so far with out any issues. When I talked with y'all about this nothing was mentioned about needing to do so.
Note: After he gets his new machine he does plan on getting the A907 done.