Each motionetc. has an extra bone animation in it that handles the size mod.
What you have to do is find and export this extra bone animation from each motionetc. and import them into your edited one.
Thing is, you have to make a new bone animation and import them over it for Every Single Animation -_-
lol seriously!? okay thanks Doc. maybe i'm better off with what i have right now. at least until i'm THAT willing to put the work into it.