CCHypno, I love the data, but if I were you I would throw out your data versus SIM teams, and maybe even human teams in the early stages of a rebuild. Versus established human defenses, the EV of going for it will drop a good amount and I suspect the 2.7 points per possession would be worth more.
The formula for finding the sweet spot would be so ridiculously complicated that I just leave it at 50 but almost always use Very Aggressive on 4th down attempts. You need to weigh the expected points of your own team based on the location, but you also need to factor in the expected points against you might be giving up in field position.