there is another way to use the deluxe dining--you don't have to eat 3 meals a day...and you can stretch your credits out. We've covered 3 days with our 2 nights worth of meals...that's 6 meals over 3 days: Easy to do.
OR you can use a snack credit for a light breakfast, have a nice table service lunch around 11:30, and the five or six hours later have a signature restaurant meal. So you'd use all 3 table service credits, but actually only eat 2 restaurant meals. That said, either way we rarely use up the snack credits in the parks...typically we use leftover snacks to take bakery items home with us. The best tip I have for anyone using the Deluxe plan is watch your reservation times, and make sure there is at least 6 hours between ADRs...if you schedule lunch for 12:30, don't schedule dinner before 6:30. With every meal coming with app/entree/beverage/dessert, you need that much time to process the food, lol.
I agree if you try to eat 3 large table service meals a day you'll probably not be able to do it.