There's a critical (IMO) bug still floating around in the game.
If you build a ship, the price per month is not correct (usually it's much higher). Then when you go and click on the ship in the fleet screen, the price changes to match the price that was said in the "build ship" dialogue.
Image context: From the build ship menu, cost is X/month.
In the fleet screen, ship cost is actually Y/month.
However, after clicking on the ship, it's cost is now X/month.
Reproduction steps: Build ship. Check cost in fleet screen, compare to cost it said it would be.
Then every time you leave the shipyard you need to click on it again, so that it costs what it actually said is will. Possibly after every battle as well, but I don't remember if that's all the time or not.