These WP electronic belt-drive models varied on behavior for Super Wash. It can be used as a stand-alone prewash by selecting it (cold wash option) and Start without a Fabric cycle. Or as a traditional Super Wash by selecting Super Wash first, then a Fabric cycle, options, and Start (no detergent dispenser so add a double-dose of detergent at the start).
The user guide for an early model says stand-alone selection stops after the partial drain, leaving the remaining water. The user is advised to run a Spin Only to drain it, then run a full cycle of choice. I suppose a full cycle could be run directly without draining first.
A later model runs a full drain and spin in stand-alone Super Wash/prewash mode.
A following direct-drive model has separate choices for both Super Wash and Prewash (and Soak).
Soak is only a stand-alone soak, drains & spins ... then the user runs the desired full cycle.