I agree that 20 seconds is an eternity....especially with my old bow. It is something I have done on only a few occassions and only b/c a great shot seemed to be ready to present itself....just never did. In most cases I was able to draw again when the deer and I settled back down. Normally from draw to shot is about 2-6 seconds.
My point was that a hunter' s ability to hold a bow without jeopardizing his shot is expanded when shooting a 65% let-off as opposed to a 35% let-off.
I seem to one of the very few still shooting such an old bow.

BTW, I just pulled my bow back and tried holding it......I obviously over guessed my ability.......by 9-10 seconds I couldn' t be sure of anything my arrow might do. even so...I would expect that to " grow" by going to the higher (65%) let-off.