The miles seem to be whatever gcmap.com uses. You will need to add the miles for each flight within your itinerary. The exception may be if you have a single flight number that goes via somewhere else - where you would be given a single boarding pass that covers the end to end journey. For example, last year the first part of my itinerary was MEL-CMB-DEL. MEL-CMB touched down in SYD for a technical stop (they merged flights). The miles were calculated as direct MEL-CMB plus CMB-DEL, even though the actual routing was significantly longer. Similarly, the route only counted as two of my permissible 16 flights even though I had three take-offs and landings.
Good luck with fitting Asia, Europe, South Africa and the US in a 35k routing originating from Australia. Plugging in the most mileage friendly destinations into GC Map shows 32,000 miles - and that is if direct connections between these cities existed, which most of them don't.
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