ATH is the biggest factor in determining how often your QB will get sacked...in my opinion.
However, I don't think ATH is something you need to worry about with this discussion. Both of your starting QB's, have decent ATH for division 2. So, anything abnormal isn't a result of low athleticism.
Instead, look at two other factors. One, both of your QB's GI is in the 50's. To me, that is low for a junior or senior QB in D2. I would want that to at least be in the 60's. Game instinct effects how long the QB takes to release the ball and how quickly he can make the correct decision. Now, that factor alone isn't why I believe you're seeing an increase in sacks. On top of having low GI, it also appears that you are targeting receivers on long/deep passes, frequently. Again, it is possible that the game logic doesn't delve this deep. However, the argument I would make is that it is taking those receivers extra time to run their route, naturally forcing the QB to take longer to throw, and the low GI is adding even more time to the release and decision making. So, those two factors combined with each other would seem to produce a high sack statistic.