One other value-related thought. We are going in a few weeks with dd10 (adult on dp) and ds7 (child on dp). We noticed that a few places we were interested in eating, such as Spoodles and to a lesser degree Rose and Crown, had kids menus which both included some real-food options (steak or chicken breast with veggies, etc.) and where a kid ordering an appetizer, entree and dessert even off the kids menu could run up a pretty hefty tab. So we figure that even if both kids order from the kids menu, we should balance out since ds's dining plan was purchased at the child rate. For people in our situation, where you still have at least one child paying at the kids' rate, maybe it will make the situation a little easier to tolerate.
Also, we picked some places (at the kids' request, actually) like Teppanyaki and Sci-Fi where we know there will be items on the adult menu that dd will eat, since they are essentially the same as the kids menu. So this and buffets where she would have to pay as an adult anyway I think will leave us feeling that we got our money's worth on the plan. We just felt the whole out of pocket thing would get confusing and we didn't want to end up with leftover credits, so this rationalization worked for us (and convinced dh that the dp actually made sense for us). Just sharing in case it helps someone.