There has to be a mouse-over div when you mouse over upkeep to show the specific amount of credit that the upkeep cost is. When you reach over 1bil it isn't all that precise. Say you have what you assume is 50 mil more than what it 'says your upkeep is' it tends to occur where that's still not enough and it damages your modules. It's not much of a need but it would help, instead of going through say, 130 modules just to see the total amount exact. (I'm also aware this usually only occurs if you're either: poor in income or working on planet upgrades.. Or installing new modules)

Yeah, I mentioned this before too, seems like a good idea.