Linking vampire forms doesn't seem to work for body types

I was editing a randomly generated vampire townie and editing his body type when I realized that neither copying body type between forms nor linking the two actually made the body type the same, the dark form was always thicker in the midsection and thinner around the limbs, no matter what. I tried reselecting the body-preset in CAS, which also didn't work. After a while, I resigned myself to fixing the issue with MCCC, which worked flawlessly.

I don't mean to rant, but I wonder why bother putting a feature into the game or refining it, if it's still flawed to the point of needing to fix it with mods? Is anybody else having this problem?

EDIT: After using the mod to get each form to have identical body shapes, the linking feature is finally working as intended, which is great, but still upsetting I needed help from a function not originally within the game.

EDIT EDIT: Nope, seems to have revert itself, his forms are out of sync once again. Quite upsetting...