As far as I know, there is a flat discount for AP holders for DLR hotels, but depending on the time of the year, there may be special deals available as well.
When wanting to use your AP for discount in restaurants/food/merchandise, the person with the AP must be the one who pays, but it can apply to the entire bill.
Haha no worries! I had a similar question a while ago and searched high and low but couldn't find anything suitable, then was given this link by someone which is now bookmarked on my browser!