[PMoz99]

I think the truth is that we will never be able to say for certain how many kills a certain pilot got, unless we can match each claim to a definite a/c killed. I think those instances are in a vast minority.
In those cases where we can't, it's impossible to say we have all the information relevant. It is fact that many records were lost.
Unless someone can reconcile the number of aircraft produced vs the number left at the end vs the number claimed to have been shot down, lost in accidents etc WITH CERTAINTY, and then match that to all the reports, there will almost always be uncertainty.
I think there will ALWAYS be instances where information is inaccurate or incomplete or censored, so to try to pin down exact numbers will in I'd say the vast majority of cases be a lost cause.
Historians and experts have trawled through all the available data. Be happy with what we have. It won't get any better given pretty much all the relevant personnel are now no longer with us, and it's now 70-odd years ago. Even the more recent wars have discrepancies.
Peter