So for the most part I understand the building income system, and how the economics system out of Ultimate Campaign works except for a conflict between NPC profession rolls and Building income. The question is Why are NPCs entitled to a profession roll while they are working at an establishment they do not own?
This came up when I offered the Barmaid if she would like to be the manager of our inn while we went to kill Goblins and her response was "No, I make more than 2 gold in tips," I and my character assumed she was stealing from the inn. Her earnings amounted to 60% of the building's total earnings. Granted We (the Party) just Got the building and it is considered "broken," but that is all the more reason why a barmaid earning 2.5 gold per night seems weird. My understanding is that the average commoner makes between 1-3 silver a day. So, I assumed that she was stealing from the Inn, and did a rundown of the inn's operations and books. My GM said they came up clean, which made me more suspicious. I admit I may have gotten a bit cantankerous at this point but this character was made to be an economic guru, and I thought I had a pretty solid mastery of the building income rules in preparation. so I pushed it.
The answer I got from my GM was, "she is using her profession roll during her shift to make the money, it reflects the tips she is getting." and apparently he had it verified by something on the forums, said by one of the devs. I can't find the post, but I am sure he is telling the truth.
So, I ask again, Why? Why is the Tip check calculated independently of the Inn's income check. It seems like the checks should influence each other. A good Barmaid should increase my Inn's reputation, and a profitable Inn should increase the tips.
I am asking for clarification, because the issue is kind of breaking the immersion for me and I want to be able to enjoy the game.
I don't recall discussing "tips" as an option for the Profession skill, in or out of context of the downtime rules.
When you have employees for a building, their income is irrelevant—the system is built to show the income the PCs make from that building after wages are paid. Nobody's supposed to be making income checks for NPCs (because the system isn't modeling NPCs earning money from their work).
I don't see how she's earning 2.5gp in tips per night. The Profession rules in the Core Rulebook say you can earn half your Prof check in gp per week. At 2.5gp per night, x7 days that's 17.5 gp per week, which is a check result of 35, which is really impressive for a barmaid—even with a high ability score and Skill Focus (Profession [barmaid]), she'd have to be 9th level (9 ranks) to even be able to roll that high.
Even if she were using the (PC-oriented) "skilled work" rules (which she shouldn't be), she'd need to be rolling a 25 on her check each to earn 2.5 gp for the day's work—which puts us back in the "how the heck is she rolling so high?" department.
So, basically, I don't know what your GM is doing. Manager pay should be an upgrade for the amounts an NPC would be earning as a normal, don't-track-the-cost employee.