It can be done
On a visit to one of the Aman resorts in Bali about 7 years ago, the GM at the hotel discounted a lower rate by about 10%(back when there was a fair amount of civil unrest in Jakarta). When I arrived, the room wasn't to my liking, so he offered an upgraded room for only a small amount more than the room I had booked. I doubt they do this routinely, but when I went, tourism in Indonesia was doing extremely poorly.