Exactly. Back in the late l970's, the eastern U.S. mostly had two types of gas - leaded "regular" at 89 (that is [R+M]/2) octane and leaded or unleaded
95 octane premium. Amoco was one of the first companies to drop the octane of their premium from 95 to 93, and the Maryland state comptroller decreed that they could no longer market it as "premium" in the state!I don't understand how 89 has now become premium rather than "mid-grade", unless were talking about high altitude areas of the west.
Tom K.