I just tried this after researching on the web and found a few others who've performed the same procedure with good results.
Erasing the system-specific adaptation values does exactly what the says it would. It erased all the adaptation values and counters for each of the clutches. You can see the values in Advanced Measured Values IDE07437 to IDE07456.
Immediately after the reset, the car shifts a bit rough. There are three types of adaptations the transmission needs to perform: quick, pulse, and slip.
A. Quick adaptation is the first thing to do:
1. ATF temp over 40 C
2. In D, drive with light throttle (60 - 100 Nm), max rpm 2100, 1 ->2 up shift, 2 ->3 upshift, 3 ->4 upshift
3. If possible, decelerate your speed without brake down to 40 kph/24 mph, let transmission downshift itself to proper gear
B. Slip adaptation is next:
4. After less than 24 mph, brake and stop the car completely. While still in D, hold brake and stay stationary for 7 seconds.
C. Pulse adaptation is done automatically while you're driving under light-medium throttle (less than 2100 rpm)
I believe this is necessary because the transmission reduces the frequency of automatic adaptations the higher the adaptation counter is registered in the computer. This is because each adaptation causes slight stress on the clutches/brakes. However, if you have new ATF or new mechatronics, you should re-adapt asap so the transmission shifts at the optimal points. Rough shifts causes more wear. If you do nothing, the system will automatically re-adapt over time, but that may be a long time if the adaptation counter is high.
So basically all I did was drive around the block a few times under light throttle, coast to a stop sign, then start moving under light throttle again. The more I drove/coast/stop, the smoother the shifts became. This totally fixed the slightly rough downshift I had from 4 -> 3.