It has been capped and could be as little $300. If you google medicare safety net and obstetrics it will bring up health dot gov dot au site explaining each item the OB's use and how much you get back.
Most Private Health Funds that I am aware are not paying anything towards the planning and management fee.

ETA: Ring 132 011 and have your Medicare card handy, that is the Medicare Patient enquiry line and they will be able to tell you how close your are to the safety net and what you could expect back.