Matt, my trajectorycalculator isn't dead nuts accurate - doesn't allow for drag/velocity decay - but it's good enough for a ball park figure. With a 40 yard zero and shooting at 45 yards, the 284 fps arrow will hit about 4.2" low. The 306 fps arrow will hit about 3.5" low. So, your 22 fps gained you approx .7"

Now, if you could bump the speed up to 406 fps [:-]the arrow would only hit 1.7" low at 45 yards.

edit: Just as an aside, a little extra info. Midrange trajectory for the 284 arrow is +6.0" and for the 306 arrow it's +4.9".