That's a good point, I did not think about reduction in power during shifting. That surely helps greatly. I was thinking of max torque generation in lower gears, so as to prevent too much input/output torque to/from the transmission, for overall drivetrain wear and tear (and in the case of an unloaded pickup, perhaps to help with wheelspin).
My '99 Camry had separate sumps, I think I only changed once at 140k and it was very red, like little to no wear (hardly scientific I know). It sure looked vastly better than what I presume was OEM 140k fluid! that stuff was very dark.
