Been checking the values and variables of people "dancing" around soot black and they seem to always land out of range and I have to say that I have no idea where the values on the Google doc are coming from but maybe they are not the right ones. I've been working with both the Doc and another one for reference: http://www.superslothdesign.com/chocobo/
Can't say for sure one is right and the other is not, but those reviewing their feeds and colors and not landing on black but always around is because maybe they should consider a middle point in between. Not saying it's just so, but maybe it helps to reconsider the values too, the formula seems to work quite well now.

On a side note, can someone clarify the proper +5/-5? The way it was worded as one going to 255 while the others to zero is a bit confusing especially when we say +5, means deeper, which means a lower value in fact.

Pears do +5/-5 what, etc?