Hi Cat,
In most instances it depends on the doctor and the time of day ie are you getting someone into the hospital that is not already there!
I am a scrouge so when my baby was born I waited in pain until 8am when the normal shift started, I could have had the registrar for free prior to this or paid $1000 for the on call doctor - no offence to any new doctors I am sure you are capable but only someone with lots of experience is sticking something into my spine during contractions

My out of pocket fee was $11 the best money I have ever spent!
A friend had to use the on call doctor in the middle of the night and her out of pocket fee was the full $1000.
You have to by law be given a full schedule of fees before any of the charges are applied (in an emergency it is different obviously). I was given all the information re cost many weeks before admission and again on admission. Your health fund can let you know the expected out of pocket costs and make you aware of any doctors who do not participate in the "no gap" agreement.
Hopefully things will progress as planned for you and you will experience no further complications and the c/section can occur on the day and time planned - this will always be in business hours hence cheaper.
Good luck