ho okey so there is some fillet improvment to do then hehe ;)

it's weird because I managed to get this kind of "triple" edges fillet in the bottom of the piece, but can't manage to get it done in the same way for the top. But that's indeed like you say maybe a limitation of Fillet mechanism in MOI (by the way, filleting looks nice and easy but i can imagine how complex it really is underneath to develop algorithmes that works with such kind of surface)

It might be something really cool to improve for users in v.3 :D

the screenshoot of the bottom part: