DirectorTsaarx:
If the Miner doesn't get any resource production until the next turn after it finishes building, then I show these numbers:
At the end of the second turn, the Miner II upgraded to a Miner III generates this many resources:
900-3250 = -2350
At the end of the second turn, the Miner III generates this many:
-2500
Thus, you are better off building the Miner II and then upgrading.
EDIT:
This math follows from your earlier statement that you are paying 750 more to build the Miner III. But since you are getting 900 minerals a turn earlier, you actually come out ahead by 900-750 = 150 (which is the difference between -2350 and -2500)
So, the real cost of a miner II upgraded to a Miner III is not 750 more, it is actually 150 less.
[This message has been edited by raynor (edited 08 February 2001).]
[This message has been edited by raynor (edited 08 February 2001).]