I had a cash and points reservation for Cyberport Hong Kong from 3/30 to 4/1 for two nights. When I book the hotel, it was cat3 therefore it costs 2800pts and USD45 per night.

However, when I checkout on 4/1, I was charged USD60 per night. And I just found out this hotel is now cat4, which need 4000pts/USD60 per night.

Is this the way how cash and points work? Thanks.