Arthur,

This is a great comment..."Going extra heavy is just as bad an idea as going extra light".

I'm currently at 74 ft pounds of KE. I have played with all other arrow weights for my bow. If I go any heavier the KE starts dropping down below69 ft. pounds, plus I get more drop in my balistics (4 inches more drop at 30 yards).
If I go any lighter, the KE starts dropping down and I get weak spine signs while paper tuning. I believeyou are correct if a person takes the time to figure it all out, they will find that there is a sweet spotwhere you aregaining the best of both worlds. I believe I have found that sweet spot with my set-up. Happens to be at 6.4 grains per pound of draw weight for my bow at it's current configuration.
Now when theday comes that I will be able to increase my draw weight from 62 poundstowards 70 pounds,then I will have to go up in arrow weight to remain in that sweet spot. I think we can all agree on that. Well, I hope so anyway. Nice talking with you all.