7 minutes is a decent time frame to rack up stats... I play 8 minute, and feel like I need to play 7 because I'm piling up stats in passing and running.
The problem is defense. If you get too many 3 & drives against the CPU, with 3 incomplete passes, then your defense gets no stats. It's almost as if you need to let them get a few yards/receptions to let your skilled players earn some tackles.
I know when I play crappy offenses, my top defensive player walks away with 8 tackles total... not including the fact that assisted tackles are glitched and not being counted.