The problem is that you are staying through one of the changes in seasons at Disney World. And the procedure at Disney World is that the rate on the first day of your stay is the rate for the entire stay. So, if you start on the last day of a Value season, you pay value rates throughout. In your case, you are starting in Peak season to Value, so Disney wants you to pay Peak Season for your ten days.
In my case, I chose to delay going to AFTER American Thanksgiving. (I'm Canadian, our Thanksgiving is in October.) To avoid this issue. If you can't, here's what I would suggest.
Do the two reservations. On the first, book for just the peak season days. Do the dining plan and buy tickets for ALL the days you are going to spend in the parks, minus 1. I'm guessing that will be nine. Then do a second reservation for the Value season, and buy just the one remaining park ticket. That is all you need to qualify for the dining plan. Yes, you spent a little more by splitting up the tickets. But you will save heaps more by booking at the value rate.
Hope this helps. If not, I hope someone can jump in to help more! but above all, ENJOY YOUR TRIP!!!
