Some have higher flat fees.

.: Quote from @Brandon Brown: I am considering switching to a heat pump with an electric heat strip for supplemental heating in our two-flat building, with plans to add a third unit in the future.

Is there any concern that the local government would ever ban short term rentals altogether?

There was already the tentative possibility of moving out of it altogether which sounds like would be beneficial in order for it to qualify as >50% business use.  

But when listing my rentals in DFW, I've been quoted flat rates by several R/E agents.

For example, an agent would collect a reduced commission, flat transaction fee, or no commission if the buyer sources an off-market deal directly.In your case, if you'd like to compensate your agent, you can include it in the loan.

My ceilings are always bright while flat paint so that is always easy.

Then what I would likely do is use self leveling concrete to make the surface level and flat.

It also is helpful to have a California LLC in case you ever sell that property and move into another state so that you do not need to form a new LLC altogether with new operating agreement, just re-register in the new state as a new foreign LLC.

In arbitrage, the owner gets a flat fee and the operator can take all of the additional revenue for themselves without taking on any of the liability.