You first have to increase the darkness level before you can decrease it. Sat, hue, and brightness do not set the color components to the following value, they modify the current color.
So if I'm understanding you correctly, it sounds like the hue, sat, and brightness modifiers perform different operations based on where they are, and I had them in the wrong location.
Incidentally, the following also works, which cuts down on irrelevant attributes and is closer to what I was originally thinking.