Travel Trailer (Park Model) in Florida - Tie Downs - Help!

Governments need money to run, and provide services.

You've obviously run across a boundary point that is important to your local government. And they've determined that a park model effectively being treated as a manufactured home is worthy of appropriate fees/taxes.

Sorry you ran into this speed bump in your plans. When you consider the big picture, I hope you make an appropriate choice and are able to enjoy your new home.