Porting the heads and blower changes things substantially... the blower is now able to move the air much more easily and with less heat generated. A supercharger is nothing more than an air pump, and boost is a measure of restriction. Less differential pressure needed by the blower to overcome restriction means more flow.

Not 100% correct. There are so many variables to consider. No one goes to a bakery for a dental filling, as no one goes to a garage to perform PD slippage calculations. Feeding it more air and limiting restrictions will definitely yield more results. The inherit flaws of positive displacement are evident in any size. The benefit is they operate anywhere in their curve, the downside is slippage (not belt or pulley). A previous post mentioned that it is an air pump. That is 100% correct. So efficiently moving air in and out is the key to success. Some shops will find that perfect combination. Some will try the same thing over and over again and be satisfied with the same result.

There are PD blowers utilizing Teflon seals on their rotors making north of 60 psi. That material seals the rotors better than an interference coating, limiting slippage from discharge to suction, keeping the Supercharger efficiency higher.