Question: Volume Note Edit

Hi,

I made some experiments with volume note edit, especially with the preset "W1 Distor". This preset comes with volume = +12 dB. Now I tried following: I reduced the volume to 0dB, and in the note edit window I increased the volume for the 3 control points to +12 dB. So all notes have the same volume as in the factory preset. I also thought that the sound of both variants is the same, but it is not. There is more distortion in my modification. Now my question is why? Obviously the difference between the overall volume and the volume of single notes seems to play a role in sound processing.