Can't remember where I read it, but the theory is that shot "bounces" around in the shot string so that complicates a situation PROBABLY existing wherein only so many pellets in the barrel have the opportunity to deform for whatever reason.

Are you saying that you would expect the same number of pellets to be in contact with something which causes deformation but the degree of deformation would be less?

We already know that rate of deformation has been reduced by all of the above factors right?