It’s probably not the same productivity rate for each hour though. Those first 3 are perhaps most productive followed by less for the next 3, less for the next

It’s probably not the same productivity rate for each hour though. Those first 3 are perhaps most productive followed by less for the next 3, less for the next and so on. So value is still produced in the later hours. At some point it might not be worth paying the same rate as is paid for those first 3 though. Too bad all of this can’t be measured accurately (in many cases).