All sorts of things can be proven to be true even if there isn't any evidence to prove it - the reasoning goes that the evidence hasn't been found yet, or its a plot by ***** (add secret organisation here) to hide the truth from the great unwashed. For example, did anyone know that
Hitler was a British Secret Agent???!!! And wait, there's MORE - Osama Bin Laden was an American Agent!!!!!!!!
Therefore, FC
must have used 87 octane for the majority of its frontline, single engined fighters during the B of B because the evidence is out there...somewhere...