Like others have said, I don't know what that includes.....
It's not outside the realm of possibility that the $580 is "reasonable".
If it includes flight? That's typically at least $200 there, frequently closer to $250-+300. One day at the park? That's another $83 for a one day hopper, $116 for a two day. Transportation: typically for band, that's a bus both to and from. Probably add on another $50 per person just for transport to and from the airport. Sometimes, there's an entrance fee for the competition, that could be added in there. Hotel room, that seems a bit steep, I'm sure you could do better, but often you're limited to locations that will allow organizations to rent for minors in rooms. Liability reasons. I know we've come across that issue before with scouts. Either they won't rent, or there has to be an adult in each room, which typically reduces the numbers to three students and one adult to each room.
I'd imagine if they're telling you $210 pp per night, it's probably including someof the mentioned costs, even if it doesn't include food.