Income discrepancy-why?

[1000yd_stare]

This has probably been addressed, but my searches didn't pull up the answer.
In both multi and single play, there is a discrepancy between the total income (say 2000) and the treasury (1000) and the upkeep (850)- about 150 gold. Is there a reason?

ver3.08, lanka, early age.

[llamabeast]

Maybe you had 150 gold left over from the previous turn?

[Endoperez]

That'd be covered by his treasury. I think I've noticed it once before, a long time ago, but I didn't manage to reach any conclusion about whether it was a bug or not.

[1000yd_stare]

I'm an idiot. I had put in orders to buy a mage. Nevermind, move along, nothing to see here......