The Perm Press cycle was designed to cool the fabrics slowly from a hot or warm wash to a cold rinse. Hot wash to relax the perm press finish in order to shed wrinkles, then cooling while the fabric floats loosely to "set" the original wrinkle-free finish before any compression occurs during spin. Partial drain of the hot or warm wash (to the point that the pressure switch resets), refill with cold agitate. Repeat. Slow spin. Deep rinse. Slow final spin.
Of course, for loads sent to a dryer, the drying cycle basically did the same thing, so one could argue whether the extra water used in the washer was needed at all.
Whirlpool and Kenmore had variations of the cool-down sequence over the years. Repeated partial drains and refills without any agitation. Some Kenmore models agitated *during* the cold refills. There was a Knit cycle for several years that had a single-stage cool down, with Perm Press still doing the double. When conservation awareness became fashionable, the double cool-down was reduced to one.
Some brands that did a spin-drain (such as GE) made do with a cold spray that started *immediately* when the post-wash spin began.
My Maytag A906 spin-drains, but does have a partial drain, refill, and brief agitation. I haven't yet determined if the drain is controlled by time or by pressure switch reset.
My F&Ps both do a *complete* drain, then refill and brief agitation.