Annie, the "
free dining" mentioned was a package they offered (could only book untill 24th of june) for certain periods of arrival. You'ld book a disney resort and a MYW-ticket and would get the Disney Dining Package for free instead of paying $38.99 per adult per night, for the duration of the amount of nights you'ld book.
The dining package is something you purchase.
You can add it to a room only discount. At this moment, they've got the BUL/BUK-code going for arrival in august or september (certain days). You can add MYW tickets to that room-only without loosing the room discount. They've also got the ZJZ-code going on. It gives you the same discount on the room as BUL/BUK, and automatically will add MYW for the length of your stay and the dining package. For both (MYW and dining) you pay full price.
You can't combine discount. So if one has booked and used the free dining code, they can't now also ask to apply the BUL/BUK or ZJZ-code to that same reservation. That would be 2 discount; discount on the dining AND discount on the room. Adding dining to a roomdiscount is only 1 discount, so yes; you can add it and it wouldn't reduce your discount.