I am shooting a 400 gr arrow 290 fps. giving me KE of 75 ft pds. Now, if I increase my arrow weight to 700 gr but the speed slows to 200 fps (which is probably faster than reality) my KE drops to 62 ft. pds.
A bow with 125 grains of virtual mass that shootsa 400 grain arrow 290 fpswill shoot a 700 grain arrow 231.3 ft/sec which is an increase in dynamic efficiency from 76% to 85% and an increase in KE from 74.7 ft/lbs to 83.2 ft/lbs. These are straight forward calculations. The only number I assumed was 125 grains virtual mass but the result would be the same regardless of what "reasonable" value you choose. If mass goes up so does KE and its true for all reasonable arrow weights.
The only place I can see where this may break down is if you are at extremes where the limbs of the bow are beginning to fail and Hookes laws nolonger apply.But that certainly wouldn't be a reasonable point tobe made here.