Strange economics

Could someone explain how this works to me:

I have a whole bunch of planets in various stages of development. I check the economy, and my net income is around 500BC. I rush-buy Terraforming on one planet, and the planet screen tells me that the income on that planet has gone up by a few, sometimes as much as 20-30BC. But when I check my economy again, my net income has jumped to 2500BC!

How do the income figures on the planet screen relate to the total income figure?
193 views 3 replies
Reply #2 Top
Nope, I had plenty of cash. My treasury was still positive after the buy, and I did it quite a number of times, with the same effect (the values varied, of course).
Reply #3 Top
Will i belive if you upgrade the planet less people die and more people are born and plus more industry and commerce come. So this makes you get more money and maybe some more trade.