Years back I did Agency work,was sent to UPS Nuneaton they had the right idea,trailer was due out at a particular schedule time, it went on time it was a case of shutters down and go irrespective if the load was complete or not.It went with whatever was on the trailer at the departure time the rest stayed.
Where I work its not unusual to sit about for 4-5 even 6 hours waiting for a load, for the last 4-5 weeks its been running nicely. I know what you mean, sitting about doing nothing is more tiring than hard work 