<blockquote>QSD-Dan: Whirlpool had many different versions of spray rinses on their belt drive machines. I'm sure the ones that spray rinsed up to 7 pulses probably did a good job.</blockquote> Our 1962 WP was *horrible* at rinsing with the high-sudsing detergents of the day. It suds-locked frequently which made the spray rinses in the interim spin useless. I recall instances of considerable suds in the deep rinse, and a few instances of initial suds-lock in the final spin.
The 1976 (18#) machine was much less chronic with that problem. Perhaps 1) detergent sudsing profiles were reduced or 2) there was a design change that eased it.
I've not had rinsing trouble with any the direct-drives I've used.