My LLC is setup in Philadelphia (PA LLC). Philadelphia has its own set of business taxes, but my LLC is setup as a sole proprietary, therefore acting as a passthrough to myself for state and federal taxes on the profits. My questions are in regard to these Philadelphia business taxes:

• Do I need to file and pay the taxes on the business first in Philadelphia, and then also pay regular state/federal taxes on top of that or is there some sort of exemption since my LLC is acting as a passthrough?
• Are the taxes calculated before or after the "passthrough" taxes have been subtracted from the profits (I'm guessing before)?
• It seems that the business taxes are directly associated with the specific rentals in Philly. Are the taxes applied only to the costs associated with the rental, or does it take into account general business accounting, where I would only be taxed on the net income of the business rather than just for the specific properties?
• Would this change regardless of where the business is setup (i.e. I imagine that any LLC operating in Philly would still have to pay this)?
• Is there an optimal setup here that would minimize the dual taxation between out of state and in state?