I heard back from Centurion travel service this week with the news that AMEX marketing had sorted out the issue with Waldorf Towers in NYC. A free night could now be obtained using the certificate at that location. Too late for me though - I had already changed my travel plans. Hope other folks get to enjoy the promo. And I hope AMEX Centurion works out the kinks ahead of time the next time they send me another "gift."