How many nights did you get from the end of May, 2008 through the end of 2008? Marriott uses a rolling 12-month window for achieving a higher elite level.

Therefore, if you had 36 night credits during that last half of 2008, then as far as Marriott is concerned, you have the 75 nights needed for Plat. ^ (Their online tool only shows nights for this year. It does not show the total nights within the last 12 months.)