I am working on an All-JohnMadd set at the present time that directly addresses this issue of the underneath stuff...There is no COMPLETE solution, since the AI tends to call a lot of West Coast offense style of plays, BUT there are slider mods that you can dial in that remedies the issue to a degree...
The issue is the fact that the timing of the deeper pass routes is OUT-OF-SYNC with the PASS BLOCK, PASS RUSH and CPU ALERTNESS/AWARENESS and the new feature that was supposed to rid us of ROBO QB....
It's almost as if the developers realized that they had a QB sack glitch problem on their hands once they programmed in the new feature that was supposed to address robo-QB, you know, that feature that causes QB's to make errant throws....
Well, while I do not have proof in my hand that this is the case, let's just say a little birdie & I had a conversation about the CPU QB sack glitch issue and in the course of our conversation I was able to deduce that once the publisher may have realized that at certain internal game speeds the game was out of sync (isn't odd that the CPU QB sack glitch problem is MORE PRONOUNCED in ALL-PRO, PRO, ie less juiced/roided up-slower internal clock, modes), they patched it with AI logic that causes the CPU QB to dump the ball off to avoid the sack...I have a feeling that the patch caused the longer deeper routes to be ditched and instead forces the CPU QB to favor the dump off route... Further evidence of the out-of-sync theory with regards to the PASS BLOCK, PASS RUSH and CPU ALERTNESS/AWARENESS syncing is when you try screen plays. They are practically unplayable without some serious modding...
Food for thought...