Actually, the octane rating should really have nothing to do with the rate of burn. It's purely an anti-knock index - the ability of the fuel to resist self-detonation. In these lead-free days, it's often achieved by using more aromatic (ring structure) hydrocarbons like toluene and fewer straight-chain varieties. Once you find an octane rating that prevents your bike from pinging, anything higher is a waste of money. A lot of people use higher octane fuel thinking that they're doing their vehicles a favour, but it's just not the case.
Of course, it could be that in some places the higher octane fuel also happens to coincide with some other factor that makes the fuel better quality or burn at a different rate. But you can't then make blanket statement about all brands in all places based on the octane number.