"There must be a heap of other efficiencies involved here otherwise it would be a close call."
It can't be in the flight attendants then. I remember carrying 460 back from Frankfurt once (not unusual) with 14 flight attendants. Only around 50 more passengers on the 380, but an extra 8 flight attendants. Mind you they are saving by using QCCA employees.
I know which aircraft I'd rather be working on as a flight attendant!