It's one of the peculiarities of the system, but you might be in even better shape if you let your Platinum lapse, but picked up the "75 nights in the last 365 days" Platinum the first Monday in March.

The reason? Renewing with 75 nights in CY 2008 would give you Platinum until end of February 2010 and then you'd have to stay another 75 nights in CY 2009 to qualify for CY 2010, but (at least as it used to be) getting picked up by the "rolling year" method on or after 1 March 2009 would extend your Platinum to end of February 2011! That's because when you qualify for Platinum (as opposed to "requalifying") you get Platinum for the rest of the year you qualified, plus the next year, plus the year after that through the end of February.

It makes sense, it's just that the result is sort of counter-intuitive when you barely miss requalifying and then have a slug of nights early on after you revert to Gold. Essentially most of the nights to qualify you for Platinum for the year 2010 occur in CY 2008 instead of 2009.