I don't think the immigration office refused based on education. Your job role is a supervisor and it needs several years of experiences to reach into that position. After graduating from a college you started that job within 3 months. That is why VO was unsure.
One thing I like to mention here. its an ugly truth. 80-90% cases, just to become eligible in CEC lots of Asian people start working in a restaurant. Most of the times those restaurant owner is an Asian too. we all know whats going on there. They create position to make you eligible. I know several people here, receive paycheck as a salary 50K per year. after every paycheck they just give the money back to the owner. Owner of the restaurant take all of these problems because either you are a family or friend , or you are paying him money or he is paying you less than minimum wage. Thats happened a lot in last 5-6 years, So VO become aware of those.
You will not hear that many cases that, you got rejected and you are a supervisor of KFC, red lobster etc.
I am not sure where Hermandeep works.