Light bulb moment.
The data is still counted by your phone of course (data is being sent to it).
Optus don't count it in their tally - you should look at the Optus App or online here for the Optus usage
Yeah I'm going to have to go with Peter on this one. The product pages on the Optus site are useless in terms of telling you what that little display will show you. The small image I can see does look like it has Optus branding around it but I would assume it's using the built in hardware/software of the device which would only measure what's going in and out of it, not what's counted and not counted. Makes it a little useless huh...