I'm still on MUT 25. I have been playing MUT since 15. Back in the ol' Muthead days it was called the "Equalizer". I can tell immediately if it's affecting gameplay one way or another. There's games that I dominate another 99 team, with deadly pancake blocks, receivers catching everything etc. Then there are games where every play my 99 Left tackle is basically a turnstile . I did some experimenting. Don't log in for a week and watch how your team plays, or go on a 9 game losing streak and all of a sudden your team plays lights out. Once in a great while you'll get a match where both you and your OP play about the same.
This is the reason why I have lost a lot of enthusiasm for this mode. You can call it user error, but I have played this mode for far too long, not to notice how it works. I wish I could play a non-biased game, but that's not what happens. I can't even remember the last time I played a H2H game where my OP was in the same room as me, lol