Although I'm not familiar with the sliders in Madden enough to help the issue, I think the first thing you need to find out is why you're out possessing the CPU. It has to be one of just a few things:
1. Are the scoring easily on big plays, shortening their drives? This is doubtful.
2. Is the CPU defense too weak? How many punts a game are you averaging? Yards per play? Total yardage? These things should tell you if CPU defense is weak
3. Your defense is too good. Same questions as above but reversed.
NFL Averages
Punts per game per team: 4.98
Average yards per play: 5.36
Average yards per game: 349.83
Using these average should help you narrow down the issues you're having, once you know the issue it's much easier to make adjustments.