I had a long discussion with one of the OSHC providers about this issue and this is my understanding:
To be eligible for OSHC cover, you have to be the primary visa holder, which inevitably means most couples/families can't take out 2 single policies as only one person is the primary visa holder, the others are dependants.
There are cases where couples have two individual single policies. Whilst this has been accepted by DIPB/Home affairs - this will not be accepted by OSHC providers when it comes time to claim. The dependents claim will not be accepted as they need to be the primary visa holder for the single policy.
The difference in pricing is due to claims costs (this goes for all providers). Put simply, dual and family policies claim more, and therefore the technical pricing reflects this.
