I usually think in terms of standard coloring for show birds rather than the genetic explanation, but I can see where you're coming from. I suppose the females would better show whether it was duckwing or partridge crele than the males.
Well, he looks fairly close to crele, but not exactly. I think he may be single barred and probably has some color genetics that are different from standard bred birds of crele coloring. Mixed color genetics, in my opinion. Here is an example of pure crele coloring.