About 15 yeas ago, GM claimed that some brands of gasoline did not contain suffient quantities of detergent additives, and the fuels did not meet federal "Vapor Pressure" standards.
Insufficient detergents tends to foul the fuel injectors prematurely, and the fuel vapor pressure effects drivablilty issues like rough idle and stalling.
GM threatened to make specific brand-name fuel recommendations. Three that did pass the test were Mobil, Shell, and Chevron.
Ford may have experience similar problems that GM had, but they can only make recommendations. According to the Magnuson/Moss warranty act, If they require you to use a specific brand of gasoline to maintain your warranty, they must provide that product free to the vehicle owner. I don;t think that Ford wants to buy everyones gasoline, just so it's BP.
...Rich