Dr Schmenge:
I'm not sure that I really understand either. However, what I can tell you is that once I moved all of the patch bus activity to the patch level (vs concert level), I no longer had the issue of duplicated AUX busses showing up.
I think what causes Mainstage to duplicate a bus is that it thinks that it is being asked to send a signal to a location that is no longer there, so it just makes a AUX bus. So, I have been very attentive to if a action that I take automatically makes a AUX strip or not. If Mainstage makes it, I use it because that is where Mainstage thinks it is sending information. I then change that AUX bus settings to what I need vs what it generated. I think this scenario is made worst if you are trying to send a patch level bus assignment to a concert level AUX. So, I no longer have concert level AUX assignments which is a pain for efficient workflow, but I get around that by having a patch level template patch and I just duplicate that template patch whenever I am making new patches. The advantage of that approach is that many of the assigns to buttons are already made.
This doesn't seem like the way things should work, but until I am granted knowledge from the Wizards behind the curtain at Apple, I'll have to make my own yellow brick road. This one is working for me.