I've encountered a bug concerning leveling elite units in cities. Whenever you buy an elite unit a level, and then take them into a real battle, the xp it'll need to level again is bugged. After extensive testing I've come to the following conclusion:
- Buy an elite below level 30 a level in a city, and the xp it'll need for the next level will be extremely high (around 600).
- Buy an elite above level 30 a level in a city, and the xp it'll need for the next level will be extremely low (somewhere between 0 and 25)
Just thought to let you know. And no, I have not deleted the elite units I've used to 'test' this.