You can book your room early if you want, and then convert to the code rate. We booked our room for December at POFQ in April and converted it to the code rate this week. The room that I booked was a Disney Club room, so I already had a discount and they applied the code.
By booking my room, I got the hotel that I wanted to stay in. POFQ is small, and it is our favorite, so I wanted to make sure that I got the hotel.
I guess the only advantage to waitingis that you don't have to pay a deposit so far in advance.