I'm curious, how did they accomodate you? We're 2 families of 5 and booked there because we "had to". Do we have other options at the mods?
Luckily our kids are young (and small) so they were able to sleep in one bed. We also "had to" book POR, because we were a family of five. Altogther we had 4 rooms between the members of our party, and all 4 rooms were next to each other. We were the only ones with 5 in our room. We figured if we did request a room change it would have caused all kinds of trouble getting us four rooms near each other again. So, we just lived with it, and made the most of our time at the resort.
If you really need the trundle bed, then I would call ahead of time and make sure they have that noted on your reservation.