That's true. It's more profitable to see which foods are selling for the highest amount, otherwise you are losing money on the crystals, and in some rare cases, the materials. I've found selling apkallu omelettes or foods that require cooking sherry the most profitable. IT could also be that HQ food is the most important one to be sold that is high-end, because that is what the players are looking for. They are also willing to pay more for it as well.
It's come to the point for me that selling NQ gear and food is pointless. Selling HQ is profitable, and using the NQ gear to turn into materia is a better use of it. I'm guessing this was SE's intention eventually.
Edit: If I could make a change, it would be that food yields at least 3 servings when crafted. I think that would warrant the use of the cluster better.
