First off, when it comes to non-steal turnovers, are you labeling pass deflections as steals? If you're not, you can increase the pass-accuracy, while also increasing the Hands and Play Passing Lanes sliders for the CPU to get more turnovers.
As for 12 minute quarters, if you lower the gamespeed to 52 and/or lower the HUM speed and quickness to 40, and the CPU speed and quickness to 35, you will get realistic results.
Just some suggestions.