That is to say, does X, Inc that produces format 123, alter that format in any material manner when it is in a small market versus a large market? Or do they assume one-size-fits-all-no-matter-what?
There is no one-size-fits-all answer to your question. It depends on the company, the market, the format, and the people involved. These radio companies compete with each other. They don't do the same thing. If one can get a leg up on the others by doing something different, that's what happens.