[Muldeh]

Lets look at it another way even..

You build an overlord -100 minerals. (due to needing supply)
You scout with this overlord, costing you 8 supply. (due to scouting)
You build a replacement overlord, costing 100 minerals, and giving you 8 supply. (due to scouting)

The first 100 minerals lost can not be counted unless it was built purely to be sent as a scout. In which case the fact that it provided supply is irrelevant, and the replacement overlord is it's own seperate cost.

PS: My ps was purely a challenge for people who wanted a real maths problem, of course it has nothing to do with proving you wrong here. I am not trying to mislead people. Actually I don't believe you could solve the problems i gave without solving the whole game!