Same here. On my stove, low would only keep something warm, not on a simmer. Each stove is different. Whereas, med would still keep it at a rolling boil. And High would have it scorching. I have an electric stove. And these settings are for the large burners. On the smaller burners, the settings are marked the same on the knobs, but you get different results on the smaller burners using the same markings. Also, the right back burner on my stove is right over the oven vent. So if I have the oven on and the excess heat is coming up through the vent on the smaller burner it will affect the applied heat to any pot regardless of whatever I may have the knob setting at. Therefor, if I put that burner on low, and the oven is on, there is the possibility that something may simmer depending on the size of the pot and the viscosity of the contents of that said pot. I then have to delve into my level of intelligence and decide what the best setting for that particular burner should be. I also have to make the decision of how well done do I want that particular item of food to cook. Well done, medium or rare. It is a liquid or solid or a little of each. Is it a protein or a carb. Each one requires a different temperature and length of time to cook. For veggies, a lot of folks like theirs crispy and barely cooked. Others like myself like them cooked to death in a rolling boil. Carbs such as pasta also require different considerations when cooking different shapes and thicknesses. Rice is another carb that needs entirely different considerations than pasta. Where as pasta requires six quarts of water to one pound of pasta, rice requires two cups of water to one cup of raw rice. And then you get into different kinds of rice. And then there are rice cookers. Rice once it has come to a boil, must be reduced to a simmer for a length of time longer than a pound on Angel Hair pasta. Yet it weighs more than the two cups of rice.
So as you can now see, there is no one answer to your question. It depends.
Sorry folks for the overly long missive.