Rangeball,
I'm assuming you are figuring your calculations from these numbers.........(with hush kit of course)
Ponder these numbers.......these are the actual test numbers for a 28"/61# Allegiance

28"/61# (measured) shot a 536gr 2117 at 237fps. (67ft lbs of KE!) From a 28"/60# bow with a 7" brace height.
Think about those numbers for a minute.[:-]

That's 28"/61#.

It seems like this cam system is EXTREMELY efficient with heavy arrows.

That same bow shot a 301gr arrow 306fps (62ft lbs of KE) and a 398gr arrow 272fps......that's losing 1fps for every 2.85 grs added.

Now take that same 301gr arrow and factor in the 536gr arrow at 237fps. That's a loss of only 69fps for an addition of 235grs of arrow weight on a 28" draw length bow! The efficiency increases to 1fps lost for every 3.4grs added.