For what it’s worth, the same ratio is mentioned in Elegy. It’s on page 31 of Elegy and page 25 of A Good War. But yes, those are troop ratios, not kill ratios.
EDIT: I found it. See this thread:
I’m confused by your last sentence; are we talking WoT only, or any art? Because if the latter, then surely the “Terror of Darkshore” video should count.