I may be wrong when I said;
Also, if I make a DIY change for example; change the Personalization from Default to a more precise speech in noise setting, then I lose the professional REM adjustments. Why do I lose REM? Because the settings will be (Re-Calculated/Re-Rx'd/Re-Prescribed) and therefore overwrite the previous REM-adjusted settings.
Perhaps REM adjustments are stored differently because I found the following instructions from Genie 2 Help and then search "Remove REM"
How to remove the REM AutoFit adjustments after they have been applied To remove the REM AutoFit adjustments, do as follows: Go to any tool in the Fitting step, except for In-situ Audiometry and Acoustics. In the Hearing Instrument menu, click Remove REM AutoFit (Insertion gain) results.