It’s dynamic pricing. Friday to Saturday and Saturday to Sunday tend to be cheaper than weekdays as explained above.

I normally book very close (same day, a few hours in advance) and often get very good last minute deals (AUD 160 - AUD 190 per night). I frequently visit Ibis Darling Harbour, Rydges World Square, QVB Hotel, and APX.

I never had an issue not finding in that price range last minute.