I read the f manual.

Let's take a simple example.

 M4 - add morph sets like morphs++, dial bodybuilder to 1

Add that morph to a piece of M4 clothing.

Conform the clothing to M4.  Dial the bodybuilder morph to 1 in the clothing.

The clothing is expected to exactly fit M4 dialed with the same morph.  It doesn't.