AS above, in the early days of charger blending, different companies offer different stages of porting(blending) and the name full blend was given to cover the maxiumum amount of porting available.
I've seen chargers in several stages of blend, from the better desribed as a deburr to the extreme what is stopping the whole thing from collapsing.
The PSD full blend, gave the maximum blend without risking the integrity of the casings and scroll.