Quote Originally Posted by andrewt
Buildings don't have maintenance costs.

All maintenance costs in the game are central as there really are no costs that are specific to a city. You could probably consider garrison costs to be specific but that's it.
That's rather simplistic.

Is that why the designers decided to try and make things look complicated by dividing outgoing pro-rata according to city population?

I would have assumed that city maintenance costs were assigned directly to the city. As things stand all the expenditure reports do is prevent the player easily determining the income from each city making it unnecessarily difficult to manage them properly.