Its all about saving money. 10 years I worked for them on reception. It went from a great place to work to a nightmare. You are now expected to work 3pm till 11pm with an added 15 to 20 mins handover in your OWN time (used to get paid for it) and then expected to break the working time regulations and return 8 hours later to work 7am to 3pm the following day. During that shift you are expected to be fully with it and 100% professional in the job will only having around 4 to 5 hours sleep if lucky. If you refuse to do this shift (its not necessary to be done, just lazy rota) then you get threatened with the sack. Any training causes or meeting are in your own time done as over time with no choice in the matter (again against the working time regulations) and only paid at standard rate for forced overtime.
Housekeeping’s times for cleaning rooms have gone from 27 mins for a depart and 20 mins for a stay over 10 years ago to just 16 mins for a depart and 9 mins for a stay over. The staff have been cut back to bare minimum and wont get any extra time or money if behind because guests leave at the last min. Reception are told by managers to go against company rules and check in no show guests as arrived so housekeeping can get the extra time so it looks like they are coping and the managers can make their large bonuses
There is set hours but also (and very often) there is "we need you to stay until x person gets here" or "someone called sick you need to cover".