Experimenting with Defensive Holding to modify the positive results of increasing DPI proves this point. King theorized that the Defensive Holding slider would likely be the best one to start with when trying to reduce QB accuracy, which was the only aspect of his final set that was still off.
But what neither he nor I could have anticipated was HOW this slider would bring about the desired results.
You might think that you'd see more defensive holding with this slider, but you don't, not even in the animations (as opposed to the penalty calls). You see more hand fighting, but it looks very realistic, and you see more of the route-chucking by underneath coverage that you see in real life. But the increase passing difficulty doesn't come directly or solely from those interactions. Somehow this slider adjust the timing between QB and receiver to make it harder to get the ideal timing and placement on each throw. Receivers are forced to make more athletic adjustments to the ball in flight, which not everyone can do, and so you get more incompletions. You also get more incompletions from QBs just sailing the ball because they mis-timed their throw with the route (and this happens even on routes where there's no chuck animation).
So the end result is that this slider does something invisible to QB timing and produces less completions (but not more picks!) and therefore lower percentages. But it does so in a surprising way.