Interesting question and I don't know the answer, however...
You are right about the paint not being flat. The wax, no matter how many layers you add will also not make it flat, though it will tend to make it flatter.
If you take an example of plastering a wall, you score the undercoats to provide a key that the next coat locks into. When you buff off wax, no matter if you are using MF, you will be leaving swirl marks at some microscopic level. I would guess that those swirl marks together with the slightly adhesive nature of the product will be enough to get it to stick.
To be honest though I guess the real answer will be so technical that I will be lost after the first line
