Chris, these are just more skintones to go with the set buffybot made, they're not meant to be Defaults. The Defaults can be found in the
first post on the thread

Basically all they do is if you choose to breed two Sims, one with a tan skintone eg. (.75) and one with a light skintone eg. (.20), their children shall have skintone somewhere in the range between the two eg. anywhere from (.20) to (.75). So you could have a child with (.45) or any of the others in the middle.
They simply work as the maxis skintones do choosing from the range of shades between the skintones rather than selecting one or the other, in this case (.20) and (.75), as normal custom skintones do when you select them from the custom panel.
Hope it clears stuff up for you? It's rather confusing to try and explain :?
It all makes sense in my head, I swear! :angel: