Getting paid for 5 hours and being on-duty for 15 hours is not a good deal. Would you want to be paid 5 hours for working 15? I doubt it!
Ciao!
I wouldn't work at a place where I was paid for 5 hours after working 15. Why people continue to work for a company they hate, where they are represented by a union they hate tells me that they are overpaid ....otherwise they WOULD quit and go to another - better - company for the same or better pay.