Many drivers might found that shifting occupied a part of speed up process and lower the acceleration. But there're several ways that can reduce or avoid that, Using the Auto/Manual shifting function of ETS2/ATS.
Now I First
define Auto/Manual shifting switch as '1'.
define Force auto shift up as '2'.
define Force auto shift down as '3'.
And I'll provide 3 ways quick shifting...
1. Short latency shifting skill
First set "Adaptive automatic transmission" to "High power mode", you can find it at Options/Controls.
When engine rpm comes up "OVER" 2000