You don't just get credit for the start and end colors. You get credit for everything in between too.
You'll get (32,32,32) half way along from (0,0,0) to (64,64,64)
Thanks for the tip. I actually wasn't getting credit last time because I had changed the starting color to gray, but after logging in today, it was reset to black, and I noticed I DID get credit. However, when I switched back to gray, and noticed I did NOT get credit until I changed back to black. So that seems like a glitch, maybe.
I've also noticed I have to end at 128, 64, 0 in order to achieve 64, 32, 0.