The 10 tonne that was carried was only on NZAA KLAX sector or Klax NZAA.
That is a 14 hour flight where you are on your own for a little more than a tea break.
By the time was was 5 hours from destination the forcasts were more that 18 hours old.so to haul gas was better than an early diversion due to weather
Hong Kong Auckland in a DC10 can become soul searching, because the mets were 12 hours old at the flight planning stage and the flight was 11 to 13 hours,
Where does one go if AA and or CH have fog?( which is always forecast to disperse by 0900 ( even at 1200hrs!)
ASSY was usually just out of range if a diversion was needed it had to be early if one was on nett fuel
10 ton of fuel in those days was about $15000.00, a lot less than a landing fee,parking fee, more fuel to get to original destination. 250 pissed off passengers , by being 6hours late.
Its not the money, its the big picture, that why one earns a command.and is paid marginally more than a 1st officer or Flt Eng.
But can retire early (56years of age) and become an armchair boffin, in retirement