The cheapest prices that I've ever seen was on http://www.asia-rooms.com but lately Expedia has had some good deals (not at the Pen). Pricing at the Pen has always been demand driven; your specific dates can affect the price by 30% or more. But even during SARS when it was a ghost town the prices of the Deluxe suites did not come down much (while the rooms were at 25% of the pre-SARS price), so it depends on what room category you want. They do track stays, if you return often it affects your pricing and is much better than FF plans.