It's more than accuracy, its also what could happen in the time it takes for the arrow to get there especially with respect to kill zone size. For example, a small southern whitetail that will tip the scales around 120 lbs, the kill zone is about 8 inches. If this deer, just steps as you release and moves 6 inches, I sure hope you were dead center. However a big bull moose or bull elk, the kill zone is alot bigger and that same 6 inch step won't make as much difference.

There's also terrain: field vs thick woods, animal attitude: nervous/relaxed, weather: wind, rain, day light

And above all your nerves.

I will max out around here on deer at about 30. i also just came back from Idaho on an elk hunt where if the conditions where right and the animal gave me the time, I'd go for 50.