I know for a fact that this chart doesn't hold up as I did it for myself a few years ago. The bow was a 2003 Pearson Freedom. I happened to be shooting really well the chosen day, averaging less than two inch groups at 40 yards.

According to the chart, and using my 20 yard pin to shoot 40 yards, my groups were hitting 16" low. Now if you look at the chart my bow's speed should have been right around 294-295 fps. The fact is the bow was shot over 3 chrono's and was actually propelling an arrow at 264 fps.

I'd say a 30 yard discrepancy isn't even a decent ball-park figure.