This is going to happen all the time. I've used lots and lots of mods which do transformations and tried my hardest to combine them, but the net result is that one way or the other, they just don't work nice. Some dictate form completely and all the others go "Add 5" and afterwards "Reset" instead of "Decrease 5".  As Bimbos mostly  both tits and asses, I only use Fill Her Up  to  change belly nodes. So far I've been very succesful at avoiding the curse, so I haven't seen any incompatibilities.