Rather than calling a call centre, I'd use the upgrade calculator which Qantas provides on their website - https://www.qantas.com/au/en/frequent-flyer/calculators.html#/upgrade - for one way BNE-SIN, for each passenger:
- If you bought full fare economy (Flexible Economy) it's 29,900
- If you bought standard economy (Economy) it's 54,500
If you can see the booking in your upcoming flights when you log in, I'd request the upgrade there. My understanding is that the priority is then based on status, followed by how early you requested the upgrade. For what it's worth, I haven't experienced meaningful numbers of upgrades until I hit Platinum.
