Actually that's not really the case, because Onyx is best thought of as a strain. Same with "Fancy" as in your "Fancy White" Ocellaris Mike. Strains are not hybrids in and of themselves (although a hybrid could be developed into a strain), nor are strains representative of easily tracked single gene mutations (or combinations thereof). As such, what makes an Onyx and Onyx is likely multiple genes, plus I also have the firsthand experience that it is not, by default, necessarily heritable nor automatically always expressed. Nor is Onyx a geographic variant (as I demonstrated with the video from the Solomons that showed the full range of black expression in percula, all residing in the same anemone in like 3 feet of water).
Pete and I have removed "strains" like Onyx (we might not have culled them all yet) but they have no bearing (in my opinion) on naming, as they have no immediate bearing on their resultant offspring. So from where I sit, ANY Percula X Snowflake Ocellaris = Snow Onyx if it gets the gene. Not because it's going to turn onyx (it's amazing how many snow Onyx are NOT "onyx" in any sense of the word), but because that was the name first used for Percularis that have a Snowflake Gene. That's why they're Snow Onyx in the calculator. If someone definitively PROVES, through documented and repeatable results, that there is something more to Onyx and it's offspring, then yes, that would require Pete and I to reexamine how we currently treat (ignore) Onyx.
We have TALKED about restoring the "strains" to the calculator, as we can still effectively use A. percula, and A. percula "Onyx", and give the same result. But again, in looking at this pragmatically...what about the Percula that is only "half onyx"...eg. all the "black shouldered" fish? Don't they impart "black too" as some are suggesting?
But I think Mike, your F1 pair from my wild pair really hits the point home. Neither look fully like their onyx parent; the female is currently a "shouldered" perc, and the male is Onyx, but not like his dad or mom. The one baby I still have...is orange with black edges only....same batch of fish yours are from. This is just one example that speaks to why we don't treat Onyx as a Gene, nor as a Variant that matters in this scenario. We know Onyx to be epigenetic in its expression (again, why is mine solid orange, as were ALL of the siblings, until they left here?). I think we also have enough evidence to suggest that you CANNOT simply "create" an Onyx. So yes, there is a genetic component, but it's not trackable, it's not readily heritable when it comes to any sort of outcross. In every sense, it hits the definition of a strain, and is therefore a non factor.