Somewhere around 1961 to 1963, Sears did away with the hi to lo agitation speed change in the wash phase of the W'n'W cycle. At that time, the wash phase remained normal speed through out agitation as did the rinse phase also stay on normal agitation. they may have done this to differentiate themselves from Whirlpool which continued that original speed shift sequence well into the early 1970s (I think) when WP decided to split the Knits and Perm Perss cyckles into two differeent cycles. PP had all normal agitation I do beliveve with two cool down drain and fill phases and the Knits had all gentle agitation as well as only 1 drain and fill cooldown phase. Knits wash time max was 8 minutes. The delicate cycle was maxed at 6 minutes and had no cooldown phase on WP. No, Sears may have done some "experimenting", but I do not think they started simultaneously agitating and filling during the cooldown phase fill until maybe 1964. I know friend's 1965 Model 70 agitated during the cooldown fills on low speed just like our 1970 Kenmore 800 did.