Batz, I agree that there is always "fudge room" in any historic k/d claims.
However, the IJN claims have been seen by historians as certainly no less questionable than the USN/USMC claims of the day.
In any case, the evidence is there that the F4Fs "gave as good as they got" in most encounters vs the A6M2, and it wasnt because the Zeros were outnumbered, because they were not.
Coral Sea, Midway, Wake, Guadacanal, the F4F units had plenty of opposition from CV and land based A6M2 units, not to mention the attack a/c.
If it was such a heavy useless POS tub, as some are keen to make it out, why wasnt it swept from the sky? Nobody seems to be able to answer that one.