Lady Zolt has a lot more "Disney Knowledge" than me, but here's my experience...
I called to book a room-only ressie with the 40 % off military discount. Got the resort ressie I wanted then.... "Thank you Ms. X. Would you like to add tickets? No thank you, we are using the Armed Forces Salute special tickets. No problem Ms. X. Would you like to add dining?
You can add the regular disney dining plan or the quick service plan to this room only discount...the deluxe dining plan is not available to this special room only discount. Hmmm...I'm not sure. Well Ms. X, you can add a dining plan any time up to three days before your arrival date. " Then they took my one nights stay deposit and said I would pay the rest upon arrival.
So I am under the distinct impression that I can add the dining plan to military special room rate at any time up to three days before we are scheduled to arrive. They did not say anything about having to cancel and rebook (which was apparently what LadyZolt's experienced)!!!
The question that I did not think to ask, and I have been thinking about it since, if I DO call to add the dining about a week in advance, will they consider that just like all packages, and therefore have to pay the entire dining plan amount and the rest of the room amount immediately (since we would be less than 45 days before arrival)??? I am thinking the answer would be yes, but not sure. Was that what you had to do LadyZolt???
HTH