The reason is:
On acoustic accordion you have reeds with its own sluggishness. After the reed is swinging, you can change the bellows direction and back ... the reed is swinging yet and will give you a fast response. So there is almost no sound loss, depending of the quality of the reed.
A pressure sensor isnt sluggish. Every move (even though it is so small) is shown. When you change the bellows direction, the sensor drives complete to zero AND all steps between your current value and zero! That is a huge sound loss!
So, you can set whatever you want. This behavior is not affected.
You would have to change the bellows direction from +100% to -100% in crazy 0,00000001 seconds and even then it would sound different from the acoustic pendant.
I would call it good-natured and malignant or comfortable and uncomfortable
This kind of sluggishness is one point what I would expect under the advertising virtual sound behaviour.
Uwe