Adding another shout out for the TIW card here. Love that 20% discount & I don't mind the tip being automatically added as I'd be tipping that anyway..
I also have to say the TIW stop DH and I fighting over how much tip. He was taught to tip 20% I was taught 15%. So 18% on the TIW works perfect for us!
I don't agree with this, but have seen reports of people doing this-
Some people on the DDP take that the paid for the DDP & divided the cost of the DDP over the amount of meals they eat & tip off that percentage..

So say the cost of the DDP was 1,000 (family of 4) and they have 5 TS, 5 QS.. So 1,000\10 = $100 a meal.. So at the TS they tip 18% of $100 no matter what the cost of the food they ordered..
I know Waiters don't like the DDP.. They get stiffed A Lot..
We saw a family of 8 on our last trip stiff our waiter. This was after they let their children make a mess, and complained that the princess were not coming fast enough..
The parents had a VERY loud convo, about leaving tip.. And agreed the DDP included tip.. I leaned over and told them it did not (wish I had never done that)
They looked right at me, then got up and walked away.
My DH felt so bad for the waiter we left extra tip, enough to cover that table..