This is one of the money saving tips that I have read before...it is a great idea!
We have been on the
DDP on our past two trips, but I am already planning those mid afternoon meals for our next trip which will be non-DDP (oldest DD will be a "Disney adult" on our next trip).
We ate late lunches at Tusker House (Tuskerhouse?) (the time just worked well for our touring plans) and Biergarten (I thought that we would try to see Candlelight Processional) on our last trip, and it was great. It was much quieter, food was great (we didn't find dried out food on either buffet), and we didn't need dinner. We didn't even eat that late - I think that are ADRs were at 1:30 or 2, and we didn't need dinner. (To be honest, after eating lunch at Tusker House, a vegetarian's dream, I didn't need breakfast the next day, either!)
BTW, we have had dinner reservations as early as 4:30. I would guess that lunch ends at 3:30 or 4, but I don't know. Hmmmm...
ETA: I found the lunch and dinner hours! At the Disney World web site, I went to try to make dining reservations. When the restaurant list came up, I can hold my mouse over the name and a little pop-up is displayed with hours. You can also see the hours if you go to dining and click on each particular restaurant. It looks like lunch is around 3:30 just from a glance.