I just went through this with a friend helping them navigate the DDP waters...
With the DDP - I think that you get 1 TS, 1QS, and 2 snacks per day per person... (someone correct me if I am wrong) I just checked on the web site and that's how it read's. Instead of 1 snack credit... So this will add to your overall entitlements.
The DDP entitlements are connected to your room, and can be used in any order you want, They activate upon check in and they are good until midnight on departure day, not when you check out. So if you plan right you can grab breakfast or if you are leaving later, you can check out, store your luggage and hit the parks, or pool, head to Disney Springs for last minute shopping and get something to eat before saying goodbye. This takes some planning but you can make it work.
To get the most of your entitlements you will have to some homework. Its a little extra work and is well worth it to make the most out of your entitlements. This way you know ahead of time on how to spend your credits and which ones you want to pay OOP for. This also gives you a opportunity to look at the menus to see what your family will eat...nothing worse than heading into a restaurant with a hungry family in tow and there is nothing that they would want...
You can also share meals TS and QS... Not Character meals no sharing of the credits, except with the 3 and under crowd. We find that the portions are large and can easily be shared. Depending on your families make-up this is a good way to use your credits, and not waste food. Here's pretty good tip - you can always pay out of pocket for something extra like a side item, if you might need a little more food to get everyone full and fueled up. Example Cosmic Rays at MK - They have a 1/2 of rotisserie chicken meal that comes with mashed potatoes and green beans, With our family (4) when our DD's were in Elementary school, easily share 2 orders... once they got a older, we would order 1 or 2 sides of mashed potatoes or one a side of fries which they would rather have. So we would pay for the full meals with the Entitlements and cash for the sides around 3.50 each. We would share the drinks that come with the meal and ask for ice water or a couple of cups of ice when ordering. Breakfast platters are another easily sharable meal for QS and you can always grab a side of meat if needed.
Depending on your family DH and I always would divide and conquer, meaning, one of us would order using the entitlements and then the other would order the extra sides paying with cash or whatever, we found it confusing to the cast member when trying to order all at once.
If you are going to share at the Table service, tell the server up front most of the times they will split it in the kitchen some though will bring you a extra plate to divide yourself. But please tip like you are ordering meals for everyone. You can always pay OOP for a appetizer if your unsure if your choices will fill everyone up, and then everyone shares the desserts.
If you want to pay OOP for a meal when the server ask are you on the DDP just say no, and they move on...
Snack Credits - can be used to create a meal, a pastry/ muffin/ fruit cup and coffee in room for a quick meal out the door for breakfast - Get the pastry's or muffins the night before, use your in coffee room or if up to it have someone go get coffee at the food court with your mugs that come with you DDP.
I strongly suggest ordering water to keep in the room Staples is a fan favorite... Also its not worth the snack credit. We use our snack credits mainly for food, once in a while on the last day if we have extras credits for Starbucks. Also bring some travel snacks from home... breakfast bars, cereal cups, crackers, can easily be thrown in a suitcase, we use one of our carry on's to bring chips, and candy or whatever... we do this when every we travel...
I hope this helps, really doing a lot of homework will help you once you arrive, plus it will cut down on the stress of not knowing...