Question... If I were to book for 2009 right now, in late April 2008, and prices increase at the turn of the year (January 1, 2009)... Do they take on the difference to my bill? Also- if I pay it in full in 2008, but the rates change January 1, 2009, do I now have a bill to pay off the difference in prices? I'm a little confused on how this would work exactly. Thank You!