Bullpens are useless exercises unless zeroing in is a standard component to help them achieve the "concentration level" needed to be totally focused. The "Concentration Training" which is the impartial result of the zeroing in process affects the pitcher to set him up so that he is pitching in a stress situation training environment.
PiC, one of the reasons you might have trouble with some folks who read your posts is the absolute statements you make leaving no room for another view or method. I happen to agree with a lot of what you are saying however to make absolute statements like the above places you in an omnipotent position. There are quite a few educated and experienced folks who read this board who might have different experiences and ideas. To state unequivically your view without qualifying statements like "I believe that zeroing in....or it seems to me....is just plain arrogant. Also as an ex pilot and classroom teacher of aerodynamics, please, I've heard enough of your throwing Bernoulli around like he was a buddy of yours.