I turn the mic distance knob and it's not affecting my sound at all...
Seriously? It was immediately obvious to me. Perhaps you guys are expecting something more dramatic, but to my ears, it sounds just like it does when you move the mikes from a foot away to 3 inches. Well, there are all the other Leslie sims already mentioned that may be more to your liking.
I'll try uninstalling and re-installing.
EDIT: Did that. No difference for me bummer. When I turn the dial while I'm holding a chord the volume gets louder but then softens after the minute it stops turning. I have no idea what I could possibly be doing wrong, but there is no difference in the mic closeness to the horns that I can discern.