Goodwill
Angryrat, Dragonman,
Is it just goodwill? Changing Haneda to Joburg is $4049 as a straight swap. I’m sure you can do the numbers at Divisor +5, or Drop Paid with Fixed Protection, for the same days away. Being ‘assigned’ the Haneda would be at the higher end of that range.
Overall it comes down to the balance between goodwill/money and workrate/disruption/engagement, how that plays out in a market with an increasing shortage of pilots and to what extent Qantas mainline remains insulated.