A couple servers (including the Brown Derby one) did something really confusing. They calculated the bill using an 18% gratuity and then
subtracted the 2007 DDP from the bill leaving an amount which didn't show a specific tip, but included a hidden tip. It was very confusing! Especially after a martini and a glass of wine

. This was just last week but I think that it will be easier with the 2008 DDP plan.