I think you’re right 10000000000GB. This page (https://www.optus.com.au/for-you/entertainment/tv-movies/mobile-tv-streaming) seems to state iview is unmetered and this blog states HD is not possible with Mobile TV active, but as the support chat showed the other day, there appears to be so many pages of information Optus staff can draw from they can present “alternative facts” and claim that applies to each case.
@Nelse, there has been a change to the pricing.
The Mobile TV streaming add-on is $5p/m on all SIM only offers (12M & M2M).
You can remove the add-on from the My Optus application. If you like, you can always re-add it. It is a month-month service and not built into the rate plan itself.