I know there was a thread about this some place, but I can't find it for the life of me ;(

Here is my question. The planet guide tells you the general background about planets. For instance let's take a fire planet, the guide says that it produces min:1,750 and max: 2,500. However out of 5 fire planets that I took over, the ore collection ranged from 600-to-1000.
Does this mean that the guide is wrong? That it's a bug? Or that there is some unknown factors (skills or orbitals) that when combined will actually produce the stated value in the guide?

Could someone please shed some light on this?