And I'm not really sure it is worth it anymore. I keep doing the math, and only if you go to the most expensive non-signature restaurants every night will you maybe save a little money. For instance, on days where you eat at a place like Sci Fi, the food there just isn't expensive enough to justify the cost of the table service credit you'd spend there. Trust me, I used to save a ton of money using the plan, but as the years went by and they kept raising the price, it is just not a money saver anymore.
I would advise you to:
1) make the ADRs as soon as possible, regardless of whether you get the plan -- trust Scoob on this, she knows!
2) Once you have an ADR for each restaurant, eat a "mock" meal using the menus posted on-line. Don't factor tips in, because obviously the plan doesn't cover them anymore, just consider the entree, the dessert and a non-alcoholic drink. Decide whether you will use your counter-service for lunch or breakfast, and maybe do a little checking to see how much you might spend there. Add in about $3.50 for each snack credit each day (that's a pretty good average; you'll spend more some days and less others) and then see if you would have spent more out of pocket or more for the cost of the dining plan each day.
Also, don't forget that some restaurants like Le Cellier will eat up two dining credits.
Again, I think the days of the dining plan saving you money are long gone. If you get it for free, go for it; I'd take it in a heartbeat, but as much as I love the notion of it, it just isn't for me anymore.