There Really Is A Week 53 from Time to Time in Timeshare Usage
Dave,
It is possible that the reason for the discrepency has to do with the fact that there is a
Week 53 
in 2010 if your resort has a Friday to Friday Check-in Schedule.
Given that Friday December 31st is the Last and 53rd Week of 2010, that means that Week 52 starts on Christmas Eve, 2010 and
Week 51 starts on December 17, 2010.
While this is a digression, it presents the opportunity to talk more about Week 53. My Sandcastle Cove Condo in New Bern, NC has a Friday to Friday check-in schedule and therefore a 53 Week Timeshare Calendar For 2010.
For those of you who own a Week 52 with a Friday to Friday check-in your resort may handle the extra week differently. But, it appears that Sandcastle Cove in New Bern, NC is telling it's Week 52 owners that if the Owner stays in the Condo during Week 52 and decides to stay for Week 53 that Owner needs to pay a Cleaning Fee of $65.00 plus sales tax. (In essence the Owner of Week 52 gets a FREE Week of use in 2010
IF they are there and actually using the UNIT both weeks).
But, if the Owner of Week 52 plans on coming to stay in the Condo for Week 52 and he or she plans on banking Week 53, or banking Week 52 and coming to stay in the Condo in Week 53 the Owner of Week 52 has to pay the maintenance fee of $550 (2010 Maintenance Fee) for each week.
Anyone with questions regarding how their resort is going to handle potential use of Week 53 should defintely contact the involved Resort.
My guess is that Management Companies will take advantage of the extra Week to get a lot of things done if, in fact, the Condo Unit goes unused during week 53.
For those of you who own a Week 52 and have a check-in and out on a Saturday your turn to go through the Week 53 shuffle comes up in 2011.
