I'm not quiet sure I understand? One up of colored what? Was the percentage of oxide, based on your total recipe, or just your oils. Exactly how much did you use?
I find bamboo charcoal mixes easier, no spots. I get a nearly white lather and a dark dark soap with 1 Tbsp in a batch with 3600g oils. Doesn't stain the washcloths, walls, or light hair.
Try activated charcoal next time, maybe with a tiny pinch of the oxide if it's not deep enough black for you - but try first with just the charcoal and you won't get drippy black lather! I don't know why Ms Natural had problems unless she was way over the limit.
I've found also that black oxide just makes a mess, black sludge and grey lather, but charcoal is lovely. And gelled, makes a lovely crisp clear black.