I think you're getting yourself a little confused on sources here. This is from Football Outsiders, who grade the line as a unit in a fairly objective and reasonable fashion; you called them PFO which makes me think you were assuming it was PFF, who attempt to grade individual linemen which I think we all agree is a fool's errand.
You are correct sir. my mistake.
Having said that, PBWR doesn't take into account how long a QB took to throw-which is central to any discussion of how an offensive line is holding up in the passing game.
And as repeatedly stated, this was the worst offensive line in the running game I can ever remember.
Again, I just want someone to tell me with a straight face that this offensive line was mediocre or better. It's be good for a laugh.