Hello Didier,
this problem with different positions of the rudders at assist on / off at different stick positions (1/3 or full range) have already been found by some pilots in Glider mode.
You can minimize this difference if you change the "Roll rate" under "Acro mode settings) by trying.
For a jet I had found the following values:
Only an example.
............................................................Default value / optimized value
Max. Turning rate transversal .........................300 ° / s 350 ° / s
Max. Rate of turn height .................................300 ° / s 300 ° / s
Max. Rotation rate .........................................180 ° / s 600 ° / s
With these values, there was no difference between Assis ON / OFF. You have to try it again and again. I hope it's just a way to help you.
With the model type Glider (Select Option -> Glider (dynamic) we were able to minimize the different rudder positions (Assist ON / Off) even with Butterfly function.
So I could turn ON or OFF the Assist (only in damping mode) in any position of the model in flight.
Why that is so, I can't say it. But it works.
Let's wait for an update or more information in the next few weeks.
Please also read here in the forum (unfortunately only in German). Sorry!
www.jetiforum.de/index.php/rex6-assist-r...n-aus?start=54#84857
best regards Bernd