As I understand it, the concierge desk has an alotment at each restaurant that takes PS's. They are alotted a certain number of tables to be reserved just for concierge guests. It's not A certain table, but a certain number of tables. In other words, Le Cellier may be sold out, but there still may be PS times available for conciege guests only. Thats why you may be able to get PS for Cinderella's Table if you are a concierge guest, while you may find that they re sold out if you called directly.
Not only that, you throw the responsibility in their court so you dont have to call at 7:00am on a certain day.
We also found that by having the concierge people do your PS for you, we received better tables.
When you show up for your dining, your name has a notation next to it that you are a concierge guest.
WALT DISNEY WORLD...BEEN THERE..DONE THAT..GOING BACK!!