Has anyone else noticed better mileage in their cars requiring 93 octane on shell V-Power vs BP ultimate? My mileage has gone up after filling up a few different times. Now with some Shell stations the V-Power costs much more as compared to other stations 93 octane, but I found a shell station in the city that is competitive with accurate pumps. For those of you in the Detroit area, that's the Shell at 34420 Harper ave. Clinton TWP, MI. Consistently $.10 cents or more lower than nearby stations. Plus $.05 cent cash discount and they take Kroger points and fuel rewards network.