That's a question only Disney can answer and any answer on here is just a guess at best as to why they do that. If you want to plan a trip, then schedule it and start making payments. Once the rates are out, then you will see how much of an adjustment it will be, but it wont' be some outrageous amount as the rates increase is generally $5 to $10 more per night than the current rate. Rate increases are historically about 4% to 6% each year. There are alot of threads regarding previous rate increases and this seems to be the average rate of increase each year.