Quote Originally Posted by Deus ret.
Hmm that's an interesting question indeed. With governors, each acumen feather equals 10% more income, but with the king, it seems to be more complex.
The perceived drop in income might also be due to the new king not having yet aqcuired virtues like 'steward' (always a pain when this 'magnificent steward' king of yours dies, especially with large land empires), 'builder' or other happiness-affecting traits (since I leave my taxes on auto most of the times the AI adjusts them to a lower level each time the ruler changes to a noob, so to speak).

There remains quite a lot to be researched on this issue.
In the second file where the brother took over first, my economy sunk a little bit, what with him having 2 acumen and no steward or builder. However, in those 4 turns he ruled, I still managed to break mostly even on my profits. The heir took over and I was losing about 300 per turn, even when not building or training. Obviously, if I tried building or training, I went down even more. So yes, losing the steward trait hurt, but with the 2 acumen king, I still managed to not go bankrupt. With the original king, I was routinely pulling in about 500-600 florins per turn in profit, even with a few build and train orders. It was the 0 acumen that ultimately did me in.