If you're checking in on a Thursday, you can get as low as S$690 for 3 nights using the Z3H code. Including taxes, it works out to S$271/night (i.e. $175) for the Executive Deluxe.

Finally including the points:
1) Starpoints = 900 points ($1=2starpoints)
2) NAN Promo = 1,500 x 3 = 4,500 points
2) Busy Customer Service = 500 points

With 1 Starpoint = $0.035, your room cost comes down to S$165/night.