thank you Less , also under the rules of gasoline,, all gas companies (their trucks) get their gas from the same tanks, Shell,Hess, race track all of them,, yes there are tanks for 87,,89,,91,,93 and the tank may say Esso, or Texaco and other names on it, as the shell truck pulls up to it to fill up with gas, to del to the gas station with the Hess truck behind the shell waiting his turn. as the shell fills his truck he has or it is in the tanker already the shell additive, ,,as the Hess does the same, they also add color, and so on,and so on, and so on jim