Eh... (first off, we're assuming everything is done properly)

it is the variation against the face. it is that you can get distinctly different effects with different finishing stones on different blades. true?

The fact is, the bevel setter is there to set the bevel. To get the edges from both sides of the bevel to meet. By the time you get done with the finisher all traces of the bevel setter and edge developer are GONE. The artifacts of the finisher remain.

Look at it another way. If you end up with a properly honed/finished blade, is there any way to tell what was used for bevel setting or edge development?