The Hilton and Conrad both seem to have increased their prices recently. I've spent the last 3 nights at the Conrad and got exec level rooms for SGD250 booked 4 moths ago. However, looked at the rates for Wednesday night and the cheapest rate is SGD330 and exec is SGD430 !. The cheapest Hilton room is SGD350 and all the windows are covered with the outside building work going on so if anything you'd think it would be cheaper.
The Conrad said they are regularly very busy these days. I haven't had a suite for the last 3 visits as they were sold out. Yes, I did check.