Even running empty the shift strategy for my truck was stupid.
In general it was just mushy and confused.
Now it shifts like it means it when it needs to. Used tuner was $100 10 years ago and I have yet to regret it.
BUT I have yet to see the 10R80 compared to a 4R70W like that though.
Just saying in my experience that is a often overlooked way to increase towing performance with a tune. Everybody goes straight to "mo powa!"
True, transmissions come tuned for the best comfort of the driver. Soft shifts make everything seem smooth and seamless which makes for a comfortable feeling, but they are hell on the transmission. If you're average know-nothing driver hopped in a new truck and it shifted like a jack hammer they would be turned away thinking there is something wrong even though those hard shifts are good for the transmission!
I rebuilt the valve body in my 2009 and put in heavy duty springs, increased the pressure, added some other performance crap. The problem is the computer still controls the shifts. It has adaptive shift control so no matter what you do physically to the transmission the computer automatically adjusts pressures, shift points, and timing to negate what you've done. When I clear the adaptive shift strategy from the computer my trans shifts like a damn rocket for about 50 miles before the computer re-learns how to compensate for my modifications. The only way to actually get the full benefits of the upgraded valve body is to tune the computer to delete the dumbass adaptive shift program.
Hard fast shifts keep the transmission cooler plain and simple. Long slow shifts feel very nice to the driver but put way more demand on the friction materials creating a ton of heat.