"Figure out which codes they can use to get the most revenue" is a billion dollar industry with many players, subspecialties and surprisingly few lawsuits.
A lack of lawsuits can just be an off the record agreement that no one benefits from the entire mess being dragged in front of the courts with public record laws, because that is how you give future Luigis ideas.
The more shady the industry, the more everyone involved is shying awaa from sunlight.
The more shady the industry, the more everyone involved is shying awaa from sunlight.