The F6F saw a lot of action during the Marianas campaign, which was widely nicknamed a "turkey shoot". Also I am sure that being on anti-kamikaze duty skewed the stats somewhat. Rather easy to kill an already obsolete enemy aircraft which was laden with explosives and flown by a pilot with little to no stick time.
While the Brewster saw success in the hands of the Finns beyond any reason, and due to their skills and tenacity I'd have to question that it beat the 19:1 ratio. Would love to see evidence to the contrary if any of you can find it.
Ted, I am only of average skill. You take the P40 and I'll take the Ki84 and if you get me more than one out of ten I'd be amazed. It is simply not a fair fight, very few pre-42 planes could beat the late '44 planes.