Whilst the DAME may seem like just a GP, they need to have jumped through hoops to be approved by CASA to issue medicals which costs them time and money. It must also be onerous as the number of DAME’s is dropping, or so I’ve been told.
The other issue is that it’s not like visiting your GP as it’s not bulk billed, so you’re paying full price.
My GP charged me $275 for my initial Police Medical which is less comprehensive than the CASA one and doesn’t require a blood test, but does take up to an hour.