I found this under the T&C's for Free Night Awards:
"(3) Free Night Awards at the following locations require higher Starpoint redemption amounts either because the hotel does not have standard rooms or the standard rooms it offers have a mandatory Full Board requirement in peak seasons: Vana Belle, a Luxury Collection Resort, Koh Samui, Thailand; The Naka Island, a Luxury Collection Resort & Spa, Phuket, Thailand; Sheraton Steamboat Resort Villas, Steamboat Springs, Colorado; The Westin Golf Resort & Spa, Playa Conchal, Costa Rica; The St Regis Bora Bora and the Le Meriidien Bora Bora, Bora Bora, French Polynesia; Mystique, Santorini, Santorini, Greece; The St. Regis Bali Resort, Nusa Dua, Indonesia; Hotel Cala di Volpe, Hotel Pitrizza, and Hotel Romazzino, Costa Smeralda, Italy; W Retreat & Spa, North Ari Atoll, Maldives; W Retreat, Koh Samui, Thailand; Al Maha Desert Resort & Spa, Dubai, U.A.E.; St. Regis Residence Club, Aspen, CO; Sunset Key Guest Cottages, A Westin Resort, Key West, FL; and Phoenician Residences, Luxury Collection Residence Club, Scottsdale, AZ. The minimum number of Starpoints for the Vana Belle, Koh Samui; The Naka Island, Phuket; and the Sheraton Steamboat Resort Villa, Steamboat, which are all Category 6 hotels, is 40,000 Starpoints per night. The minimum number of Starpoints required for a free night at the other properties listed, which are all Category 7 properties, ranges from 31,500 to 140,000 Starpoints per night depending on the hotel, its category, its room types, the time of year, and/or it’s mandatory requirements. Redemptions at these hotels must be booked through your local customer contact center."
Since the cost in Starpoints can be affected by multiple possibilites, you would need to call in to make an inquiry on your specific travel dates.
Best regards,
William R. Sanders
Social Media Specialist
Starwood Hotels & Resorts Worldwide
[email protected]