FS HK is high occupancy, has apartments, and i believe many nonguest customers for dining and spa. a business traveler here reported difficulty negotiating early/late checkin/out.

IIRC Peninsula HK was one reported (in amex forum) to not honor FHR 4pm

(and HK is a busy city, including for luxury hotel market)

the amenity, as well as breakfast, are designed to get guests to spend more (above credits)