No worries, I‘m used to communicate in English.
I really doubt that the transmission has anything to do with it. Does the engine run smoothly in Idle mode at 550rpm? How is the behavior with active A/C when turning the steering wheel? Maybe a slight idle rpm increase will fix your problem.
The engine idles at 660rpm (is the n55 suppose to idle at 550rpm?) according to ISTA to but it does have a occasional +-50rpm shift which apparently is normal, With AC the surging is more pronounced, also the car has light pulsing when in gear and brakes applied I think NIC (Neutral Idle Control) is not engaging.