Is there a difference in the quality of gasoline according to the oil refinery company?

pu1. I don't know if it's because of the refinery or the gas station, but I think there's a difference

2017-10-30

OK

pu2. I think there's a difference. That's why I usually put it in direct management

2017-10-30

OK

pu3. I heard that gas stations use other companies' oil, so just because you go to one of the refineries doesn't mean you use that company's gas

2017-10-30

OK

pu4. Wouldn't you be able to believe that it's directly managed by the oil refinery?

2017-10-30

OK

pu5. I heard that s oil for regular oil, GS for high-quality oil, and Hyundai Oilbank are good

2017-10-30

OK