So we met this past weekend with our caterer and she did a breakdown of costs for food , drinks and what not including the 18% gratuity, As I was looking over her breakdown (after we left) I noticed the tax at 9.25% for some reason came to more than the gratuity so I called her well anyway it was wrong but when she told me what the correct tax was I noticed that she included the 18% gratuity into the amount she used to get the appropriate tax ... is that right? Do they usually tax on the tip?