Fair enough. The customer may order some soft-drinks or alcohol drinks at the bar. Also I hear deserts are high margin. My point is that relative margin is not the thing you would want to optimize on. You'd want to maximize profit per customer per hour.
His point still stands. Your original estimate of the margin was just not realistic.
This obviously varies depending on many factors, but when you factor in labor, ingredients, equipment etc. 10% is a good margin on food. In your hypothetical example the customer who came in, had a meal and nothing else, and then left earned the pub $3 in profit. Someone who has a few drinks in the same amount of time will usually generate more profit.
