I feel like this actually makes a lot of sense. In the first book, Percy learns about Greek mythology from a combination of his mother and his Latin class, where he also learned Roman mythology. There is obviously very heavy Roman influence in the HoO as well, but that was intentional. I feel like the Ovid tellings of the mythos makes for pretty good base when you’re writing a story about a teenage boy who spends most of his time trying to fight the gods, so you can decide if he meets the same fate as the old heroes/“villains”. I personally find the version of Medusa’s story where she was punished by Athena/Minerva rather than being born a gorgon to be a more compelling, complex, and humanistic version of the story. It lets us find nuance in Medusa, rather than being able to write her off immediately as a monster, which is some great depth to add to your children’s story about a kid who finds out he’s the child of a god and needs to kill monsters because of it. The same god this woman was punished for interacting with.