“Top Tier” gasoline is nothing new, the requirements and designation began at least 12 years ago, maybe more if I recall. It began when GM, BMW, Toyota, and Honda set out specifications for fuel detergency and additives that helped keep injection systems and engines operating properly. The EPA standards for fuel quality had been lacking and Top Tier was an industry effort to keep up with the technological needs of the cars on the road.
Oxygenated fuel is also nothing new, it’s been in use since 2006 or earlier.
Oil companies are also free to introduce their own brands of additives and supplements into their gasoline, and some have differing amounts of detergent depending on the grade of gasoline.