I haven't done a thorough statistical analysis to definitively prove this notion, but I'm almost certain from observation that the number of first downs gained through penalty is way, way below what it should be. I think in an average NFL game u can expect at least 2-3 per game, and I'm almost never seeing any.
I'm definitely sure the number of overall first downs is noticeably low. However, offensive yardage, which I have done a complete stat analysis of, is being gained at a very realstic level.
Therefore, the obvious conclusion we're ;eft with when taking these two factors together is very likely that not nearly enough first downs by penalty are occurring. Bump up this AI setting or whatever it is, and more first downs will happen, then more points will be scored(points scored is def low, noticeable enough to not require a thorough stat breakdown).
I see the expected number of penalties overall, but a noticeably inordinate number of, for ex, resulting 3rd and 5's, rather than "automatic first downs", which I can hardly remember seeing at all.
So, even though the overall number of penalties occurring feels right, it is the type of penalties being called that is not reflective of a real pro football gane and needs to be adjusted for more optimal results.