Quote Originally Posted by Stig
I doubt it, you get to choose if you make a city a trade or production centre. And using my Dutch logic I would say that only trade centres give you money. I could be wrong ofcourse ... tbh most of the time I am wrong
You are wrong.

Castles still provide you with money, just not as much.

Some of the screenshots posted show cities and castles with 10 units in each of them and none of the settlements are making below 1000 florins. Most are in the 2000-3000 range.

Upkeep costs = too low.