Mirroring doesn't work with most avatars, chest proportions doesn't work with most avatars, 3DX standardizes all avatars so why doesn't all avatars work with Character Proportions?

If I import a character from FBX and then need to use Character Proportions, if I need an identical model perhaps with improved weights or change a UV map I have to use a notpad and write down all the proportions. It would be easier to have a save and load button right on that panel. If I save the model all proportions become 100% so I have to use a notpad and write down all the proportions. So tedious.