Interesting what this guy said: "Something I found out from working in the refining industry for the past 18 years: All the gasoline in most markets comes from the same refinery(ies). Same 89 blend from the same blend tanks. Ditto the 91 or 93. The difference is that the trucks (branded suppliers) show up at the loading racks with a measured amount of their proprietary additive packages already in their tanks. The gasoline is splash-blended (literally!) in the tanks and further sloshed on the way to the stations for delivery."