Variable crewing levels? He he, sorry Sydgirl you need to spend some time in the rostering/crewing office...
Lets imagine we have a SYD-HBA flight with 36 booked each way. Aircraft departs SYD and 5 more pax book for the return flight. Are you going to teleport the extra crew into HBA or just tell the pax to P*?? off somewhere else?
No, I know - we'll just have 70 crew on standby in each and every port every day - just in case. The FAAA will be right behind that one dearie.