Some more data - the swimsuit I modeled earlier and rigged with your version 102 CR2 appears to be much closer to symmetrical, at least in the problem area (armpit/breast).  It may be that the number of bones plays a part (certainly that would affect the order, in a counting sense, in which bones are loaded, since the hands have been deleted e.g.) .  There is a very very small difference from left to right but it's pretty much negligible.  I will upload this version to your dev site and let you look at it (or not, as you prefer).

edit: heh I see the directory structure was recorded wrong in the previous version anyway, it wouldn't have loaded

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