Should I be charged a modification fee?

I have a rental unit in Florida. I had a new AC unit installed for my condo. The condo association charged me a $30 unit modification fee?  The fee was just to write a letter to the AC company doing the work, and that letter needs to be send by the AC company to the city government. Is this legal? I don't remember voting on any fees charged to owners for unit modifications (install new AC unit on roof)