So here is a New Product blurb from the July 1956 issue of 'House+Home' magazine about the new dishwasher.  Sounds like a great machine.  A black-and-white picture accompanies the write-up:

"Deluxe Waste King dishwasher is completely automatic, features individual control over any part of a 5-phase 37-1/2 min. washing-drying cycle.  Centrifugal pump circulates water at a rate of 60 gal. per minute.  Machine's "brain" is a control panel with 5 lights indicating each phase of the cycle.  You can set machine at any operation just by turning control knob and pushing in.  Power pre-rinse flushes away loose food particles before detergent washing begins.  A "hold-over" second rinse holds water in cabinet until it reaches 160^oF. before beginning last rinse.  Given Mfg., Los Angeles, Calif."

Eugene, I believe prior to the WK, the only dishwasher that had extra hot water was the Youngstown Jet Tower because it had its own little electric water heater in the cabinet next to the dishwasher that heated water to 180.  Yes, the WK paused to heat the water before it circulated for the final rinse.  And it was a full fill of water.  KA didn't have a SaniRinse until the KDS15 and it paused to heat the water and it only did a partial fill.  I have a sneaky suspicion this final heated rinse was one of the reasons why my dad opted for the WK over the KA KDS14.   And KAs didn't heat for the first fill until the 19 series. 

Thanks Hans.  When I was writing all that, in the back of my mind was Apex, but I wasn't sure.