I used to work for Shell
Oil and then for Tosco who was bought out by Phillips and then merged with Conoco. I supported the trading floor for their
Oil movements system.
There are probably 100 different kinds of gasoline for retail sale in the US based on regional requirements. (often at the county level). None of that is brand related.
a "standard" unleaded gas will move down the pipeline to a region and at the terminal the additives get blended with the gasoline to create the brand. The additives are different and can make a difference. ( I personally prefer Chevron techron )
This allows companies to do "Exchanges". for example lets say Exxon wants to sell gas in Wisconsin but doesn't have a refinery close to their. Shell will ship gas from their refinery to an Exxon terminal and the Exxon terminal will add it's additive and make it Exxon gas.
Many Terminal service multiple brands and will have additive blends for each of those brands.
If a region requires RFG or MTBE or another type of specialized gas that is blended prior to moving down the pipeline.