I don’t recall us having much ‘lead time’ for this job, so the Jet transit time from Jandakot would have been an issue.
You're speaking from a pilot's perspective. You said yourself that there may be hours between when the job comes up and when the crew are tasked. How much time elapsed before you were called in this case? You would not have been tasked immediately.
I expect most permanent staff are required to get their own accommodation
I very much doubt that. Hence my claim re the 7-10 houses. Perhaps Towering Q can enlighten us, based on his time at Port Hedland.
... lets stick to the factual $20K
That figure is from the pilot's EBA. What about the nurses and doctors? You have just shown that the total remote allowance for just the pilots is about $100K. Add in those for the extra nurses and doctors and you will be already near one quarter of the way to that million dollars. Now add in the housing (including utilities).