I still fail to be convinced by either side in this. There's just too much conflicting evidence, couple that with personal interpretations and, in some cases, a "multiplayer advantage" agenda and it's a royal mess to keep track of
That's why i still think the best way is to have all possible variants in the sim, especially since they will be the same 3d models (the only thing that would change is the engine parameters).
So when we open up our aircraft selection screen, we would have:
Spit Mk.Ia 87 oct
Spit Mk.Ia 100 oct
etc etc
Me 110 low octane
Me 110 high octane (DB 601N)
and so on.
Then the player can choose what they want to fly in single player and the server admins can choose what their campaign will depict. Even more importantly having both variants allows for better dynamic campaigns, both offline and online: if your fuel supplies get bombed your side has to fly on 87 octane until new shipments come by ship convoy, which would then be targeted by the opposition and epic fights would ensue protecting that AI ship convoy.
Apart from debating for the sake of historical scrutiny which i can understand, in terms of gameplay this issue is blown up way too much in my humble opinion. Give me both high and low octane versions of the flyables, a script to track fuel supplies and a whole lot of tactical and strategic possibilities open up.
Having just one version of the flyables no matter what is just a sterile representation: it's like modeling an air show piece, not an aircraft during war that depends on a host of other factors to operate at its peak ability.
If i bomb the enemy's fuel dumps and their aircraft are slower as result, i have an incentive to try it and the other team has an incentive to stop me. If the aircraft fly the same no matter what i bomb (because the "slow" version is not modeled), i have no incentive at all and we can all just hug the white cliffs of Dover and keep flying furballs on the deck until battle of Moscow comes out
Nothing wrong with flying for fun, but why limit the possibilities of better dynamic campaigns by giving the mission designers less to work with? I don't get it, after all for the majority of pilots who get bounced +12 boost will not make much of a difference anyway. It's not the instant win button many think it is. It's just something to use on the climb out to an interception, or on a long chase at lower altitudes.