Supply Quality Math (White Giant)

I have scoured every bit of discussion and documentation that I can find for the relatively new way that supply quality is calculated. It used to be that it was averaged over all individual units of supply, regardless of cost. About nine months ago, the GM announced that it had fixed this loophole, and weighted the averages. But they didn't specify HOW they weighted them, and there are several possibilities. Does anyone know the actual math behind this? I want to try to cut costs if at all possible. Thanks!

Check Wildeye's guide in the General section.

Thank you, WD!