I don't know, but I never trust any of these systems. I coincidentally watched part of a vid recently of someone who made their own ELO ratings for MMA.
Things like stylistic difficulty of match ups, wrong decisions, and basically all circumstances going into a fight won't get taking into the calculations, so I don't think they will every be 100% accurate. But they are still a handy tool, and probably a better system than letting "journalits" do the rankings.
Oh and fouls, don't know if they make any kind of difference. Like I don't consider the eye poke shinobi's win over Gunnar as a legit win.