Genetic percentages are not a wild guess, unless you don't know where your chams come from as in wild caught ones. when the kammers put percentages on their crosses its because thats what they are. If a black person and a white person have a kid its 50% black and 50% white. So if a known ambilobe and a known nosy be breed the offspring would be 50% of each, the colors just may not reflect that. Just because it looks more like one or the other doesn't mean it isn't half nosy be and half ambilobe. Just like with humans. If your mom is 100% polish and your dad is 50% german and 50% native american you are 50% polish, 25% german, and 25% native american. From how it has been explained to me it works the same way with panther chameleons. But I'm sure if you e-mailed the kammers they could explain it in better detail than I because they have many many multi-generation cross bred lines of stunning panthers. Hope this helped clear up the confusion.
Justin
P.S. I don't think the kammers would put exact percentages on the babies if they didn't know the exact percentages.