When we used DU last year I was able to get a quote & actually made my reservations a year in advance. They did initially tell me that the quote they were giving me was subject to change due to the probable yearly increase in WDW prices. The prices did go up, but DU was ultimately able to get me a price of about $1000 cheaper than my original (yr. in advance) quote by using codes & special promotions. Anyway, to answer your question, they did give me a quote a year in advance last year.
Have fun planning!