Many locations are now puting ETOH in their lower octane gas .....that raises the octane number & they sell it as premium. In reality this kind of premium has much less energy/ gallon than pure gas with the same octane rating, or even less energy / gallon than pure gas with a lower octane rating. You will not go as far or as fast with a premium fuel that has ETOH in it!!!!!! In fact, the pump that says 87 octane may have a much higher real octane rating if it has ETOH in it .....all they are required to say on the pump is what the "minimum" rating is of the fuel. It's even possible that if ETOH is in every grade of gas at a station....that in reality it's all the same.....maybe all is 92 octane.....they just list 3 different grades to make people that want to think they are buying premium. Only way to be semi-sure of what you're getting is to question the owner of the station & maybe even ask to see his invoices.