I told Patchou about that in the beta testing and he said something like "these small problems can be considered known limitations for now… I’ll look at these problems when I’ll have more time" (he was talking about other things too).
IMO the best would have been that the setup copies the msgplus2 registry settings into msgplus3 or just msgplus. Maybe another work arround is having a key in msgplus that points to the current version keys (msgplus2 or msgplus3 or etc....)
Anyway, I don't think he changes that soon
/ 
