Dan, GE introduced those in 1960. The sad thing about the power shower was that the Plastisol around the little shiny fitting where the hole in the lid received the water had an usually high rate of failure and most of them you find have the raised, irregular surface that means rust has set in.
Since the impeller was on the motor and the motor was in the reverse of pump out during the wash and rinse, it was easy to have it recirculate water to the power shower. When the motor reversed, it drained. So much like the FilterFlo washers, yes?