#rotor blocks are quite different than cascades, they do not use impingment primarily; they are more of a pin style cooling methodology, with the twist of being easily manufactured (not really but once you get the hang of it it's not so labourious
). Cascade blocks have nothing to do with pin style cooling - the main portion of cooling occurs as the water hits the bottom of the holes. A pin style block absorbs the heat from the pins as the water travels through. Pin blocks benefit from a central inlet, and possibly from some sort of jets but the two designs are not the same in cooling theory.
Correct me if I'm wrong, but I think you're getting block styles a bit confused.