It's also by far the most expensive.
The 180GB of data used for the tests would have cost them - assuming "BYO device" plans and that Telstra did not give it to them for free:
On the "Large" (50/30GB) home wireless plan:
$150/month + $1300 for the 130GB extra used during peak times.
On the "M" (25/15GB) home plan:
$100/month + $1550 for the 155GB extra.
On a "M" mobile phone plan (10GB):
$45/month + $74,800 for the 170GB.