Co-payment should include all patients
Mandate the co-payment to be 50% of any additional fee above the Medicare fee, topping out at $5 (i.e. when the patient is charged $10 or more above Medicare, the government takes $5).
Consider allowing the doctor to accept any and all payments above the Medicare fee with direct Medicare billing all in the one transaction (i.e. without having to create a private bill first, then have the patient seek the Medicare rebate).
The advantages of this would be:
1) All bulk-billing will remain as at present, because today no doctor wants to start upsetting his bulk-billed patients by adding a private fee.