This has been pretty much my experience as well with the cpu running game.
On the user side though, I've had a weird experience. Started a new franchise last week and through around 8 games my HB tandem was averaging around 5.8 and 6.5 ypc. It was too easy, I was destroying the cpu on the ground. Then it was like a switch got flipped and they were barely able to avg around 3 ypc the rest of the season. Maybe there was a tuning update or they AI figured it was too easy and automatically adjusted something?