I confirm that this long-standing problem is still present in the latest build of MC.
One observation I made, subsequent to my previous posts, which may be a clue to fixing the issue:
ARC seems unique among VSTs I've seen, in that the selection of any preferred "measurement" preset in any host/instance of ARC "sticks" globally (trans-host, trans project). In other words, the stored measurement selection is not memorized in any host's project file (or in MC's memory of the loaded VST's 'settings').
If you change the measurement selection in any instance, in any host, close that host, open any project in any other host, OR add the ARC anew in any other host ... the measurement selection will be whatever you "last selected", wherever did it.
It's like the host has to be able to fetch the setting from outside itself (e.g., the registry, some external MRU Most-Recently-Used data perhaps?) rather than within its own memory of the VST's settings.
This capability must be part of the VST host standard, as it works great in, say, Steinberg's own host(s) (e.g. Cubase), and every other bona fide host I've tried (e.g., Plogue Bidule, ProTools, etc...). MC is the only VST host which seems to have a problem related to this.
(Hoping this helps.)