I have found with DEF AWR at >68 the CPU defenders never make mistakes. They basically mirror the HUM player's on-ball and off-ball movement exactly. Do you know how in Madden the DB's in man coverage look less like they are watching the WR and more like they are invisibly chained to the WR? That's what it looks like to me. Personally, I would never recommend exceeding 68.
OFF AWR seems to make the CPU a little more aware of defenders, teammates, etc. But I think it can also reach a certain number where the CPU will look inhuman and rarely make mistakes. It's harder to determine what that number is (it may also be 68) since on offense you are not tied to a player, but a scheme. I have mine at 75, which gives you some of the CPU offensive intelligence of levels above Pro without the *alleged* impropriety. I want the CPU to play like a good, smart human with a simulation bent. I think I've achieved that @ 75. No need to move higher, or you invite shadiness.