You are getting confusing answers. Here is the thread with most answers for you (or search 2010 Armed Forces Salute):
Disney tickets (under normal circumstances) are not refundable, if you are buying them to do the free dining. I think that is a dead end for you because of the purchase deadline for the military 4-day tickets. But, if you are going to WDW in the future, you can hang on to the tickets, because they never expire until the first day you use them. That might be helpful to you.
For me, the 40% room discount works better than free dining. We will go over to Shades of Green when we get there, and pick up regular MYW tickets. For the 10 day tickets we need, the 4-day military tickets won't work. There is savings to you on the MYW tickets, because you don't pay tax. Depending on how many days you go, the military 4-day tickets might not save you that much. Here is the Shades of Green web page with WDW MYW
ticket prices. Just pull down the price window for options such as Park Hopper.
If you want the free dining, you can get the 1-day base tickets and
take them to SOG and "trade them up" tax-free for MYW tickets with number of days you need. If you buy all your days' worth of MYW tickets in advance when you book your free dining package, you will pay tax on all those days' tickets.
Whatever you do, act quickly. Resorts are getting full in Sept. because of free dining guests.