When you look at the local rates, don't think in terms of "Well, she is younger/thinner/whatever than me so I should charge less than her." The fact is, you are not competing against providers who look nothing like you. You are competing against those who look similar to you. It's not like a man will look at what's available and say "Ah... can't afford the young blond with big tits. Guess I'll take the BBW MILF." BBWs and MILFS make money because the men who are attracted to them will pay to have sex with them.
The GFE used to mean "will kiss and act like she likes you." Now, that is pretty much standard and so it pretty much means "normal, affectionate, maybe vanilla sex." It really only means something in relation to the Porn Star Experience, and even that is vaguely defined.