No he's saying your input into the transmission is the Turbine speed. The turbine is driven by the Impeller which is bolted to the flex plate and always the same as engine RPM. Turbine speed is what the transmission is actually seeing for input speed but it's not physically connected to the engine unless the torque converter is 100% locked, thus your OSS or output shaft speed is going to be calculated by taking Turbine or "input" divided by the current gear ratio. Of course you can have clutches slipping which change this. But The ratio is determined by any combination of planetary gears selected, thus giving you your final OSS drive ratio. The formula is INPUT/Gear ratio = output, or turbine/current gears ratio=OSS. If the converter is 100% locked you can use engine RPM, otherwise you must know the slip amount in RPM or the turbine's RPM to target a specific shift point. This is why you're commanding a "lower" RPM and it shifts where you want. This means your converter is still slipping which is why veefour said to lock it up faster and sooner. I can't log my turbine speed so i am tossing rocks in the wind if my converter is unlocked or slipping during the shift. This video helps illustrate what's going on. https://www.youtube.com/watch?v=bRcDvCj_JPs