How much should you pay your head-chef? Does it somehow related to the profit margin and your COGS (food-cost)? In my humble opinion, it is a direct relationship. And that is arguments why:
Nowadays many cooking schools graduate well-skilled chefs. They are good at food production, they know how to maintain hygiene, how to track expiration and many other things about modern F&B. At the same time, nobody will argue that there are good, well-skilled, and gifted chefs. Sometimes, to be honest, the well-skilled chef just can’t cook tasty food. Don't ask me why! Just can’t. Even though they spent years in the industry. And a very few proportions of chefs know the technology, able to cook tasty food and they grow professionally from year to year. A good chef will add more value to his dishes. If average around the industry food cost is 30%, good chef can lower this ratio to 25% or even less sometimes by increasing the price to procure quality food, sometimes by decreasing the volume of ingredients, and very often both (just recall how expensive the food is in really good restaurants with celebrity-chefs and how small are the portions there).
CONCLUSION - hiring a chef for the above average market salary, think - would he be able to increase your profit margin just because customers will be happy to pay more for his cooking or get less food for the same price? It does not mean that you should increase the price or reduce the portions, the question is - does it worth to overpay?