To elaborate further...
Why give up trajectory to gain a trivial amount of momentum when your setup is already packing that much energy?
As long as I'm over what I consider a minimum adequate amount of energy/momentum for the distance I'm willing to shoot I wouldn't give up any speed for energy.
Actually I think this was answered several times in the other thread. Several people said that delivering energy over the minimum needed only winds up wasted in the ground after it passes through the deer.