Govt already mentioned that the subsidized oil has the same quality like the regular one. Note that if oil is using the same logo with branded one, the it may tarnish the image the brand

Even Toyota is using Lexus brand for its luxury lines, but then both Toyota and Lexus series look the same, it is annoying

In Lotus, the oil is sold at counter, not something you can pick from shelf. This probably to prevent foreigners from grabbing but I did not see real enforcement anyway.

You need to go early morning and when making payment for another stuffs you bought, just ask if the cooking oil is still available. Each person has limit probably 2 max, I'm not sure. They get finished real fast because those people in stall business cleared them fast I think.