Are you able to actually confirm the instruction explicitly/officially comes from NESA first hand (not by deduction/speculation) and not someone else? My view is informed by a particular recent experience on this site (not going to say it explicitly but you can read between the lines). I’m still skeptical as it just doesn’t add up for me.
The schools that are licensed to administer the HSC overseas are all within 3 hours of the NSW timezone.
Also, there are controls in place for it according to this:
At the same time as more than 70,000 year 12 students are completing their first English papers in exam rooms around NSW, about 60 students will be doing the same paper in Singapore.
www.smh.com.au