A long long time ago I had a job in a refinery weighing in and out the trucks that came in from the various brands of gasoline.I noticed more than one driver climbed up on their rig as it was filling. with a small jug (a couple of gallons or so) and dumped it into each of the tanks their truck is divided into. I asked a couple of them what that was all about and each assured me that that was the magical ingredient they advertised that their gasoline had that nobody else had.
Der Fish
This is correct.
A former business bought over 1,500,000 gallons of Jet-A and 250,000 gallons of AvGas (110L) a year.
All additives, including Prist, were added in the transport tanker before leaving the holding tank which are very rarely at the refinery. Almost all fuels are transported from the refinery to distribution by pipeline, or sometimes by barge tanker, then pipeline.
Fuels are all the same. With the exception of octane, any add-ons for branding are added after leaving the holding tank.
I'm not sure about distribution or refinery capability in the DR.