I have to ask...are they reservations for the same show?? If so, did you really pay twice for the same night?
Anyway...I have heard varying reports on how they assign seating...when you originally book the reservation, when you pick up your tickets at your resort and finally, when you show up at the podium that night. I booked for our first HDDR about 9 months out, however, Hurricane Charley shut FW down until the day after our showdate. So, we had to rebook, for a different show about 5 days later. We ended up in the balcony, on the side. Not bad seats...just not where I had hoped to be. We were, also, the second party to check in. We also didn't get our tickets until 2 days before the night of the show.
When we did the Luau show at the Polynesian, we booked about 2 months ahead of time. We picked our tickets up the day we checked in (about 5 nights before the show date), and we were about 4th in line at the podium that night. We ended up with a table dead center, and one table back from the front of the dining area..very good seats.
So...to answer your original question...I don't think anyone knows, for sure, how the seating is really done. I would plan to get your tickets asap, and then show up at the podium as early as you can.