No, you’re not understanding. You’re cherry pick one outlier (Iowa is a terrible example, Minnesota is fair) and saying “See? My conclusion is correct” when in reality it is merely identifying outliers. Case in point, the team you ignored, Penn State. Penn State is in the bottom 5 of the conference for plays against per game (1.67 less than Illinois), dead last in the conference in time of possession and yet they sit in the top 5 of the conference for yards allowed per play and 3rd in the conference in points allowed per game. This tells us that if outliers make our statements, your plays per game and TOP analysis as it correlates to overall defensive play is essentially invalidated. I don’t actually believe that 100% but I can clearly make the case that it’s accurate if I only pay attention to outliers.
This is an equal blame situation. If you give up a high number of yards per play, your number one priority should not be to limit your plays, your number one priority should be to give up less yards.