you are getting into semantics. You know what he meant, as we all did. Because you offer more detail doesn't make him wrong because he generalized. Everyone knows the limits of generalizations. Did you expect him to write a scientific dissertation? Your argument could be taken apart just as easily. For example, "a homogenous mixture that all ignites simulatneously [sic]" simply doesn't exist. Nothing, even nuclear fuel exploding in a hydrogen bomb or the "big bang", explodes "simultaneously." IT can be very, very, very close... but can never reach that limit. But would that add to the discussion? no, not really, because everyone understands that, and you didn't mean it absolutely literally. None of that helps anyone get anywhere.
Semantics, that is. Go into all the detail you want, just don't attempt to misquote others, especially when doing so for the purpose of applying a logical fallacy.
However, there is something to note, though. If the octane rating of the fuel is not "high" enough for a given engine configuration, detonation can occur prematurely (the fuel isn't stable enough for the environment). What that translates to is decreased efficiency, and in extreme cases (of time or degree), engine damage (or simply a failure to run). Nothing is gained from using fuel with an octane level higher than what's necessary to prevent premature detonation.