SORRY... PLEASE IGNORE MY PREVIOUS POST.. IT UPLOADED BEFORE I FINISHED AND THE THE EDIT TIME EXPIRED.

Ok, I'll try TO help you out here, but please know I am just a novice at this. But hey.. I did get to work after spending many hours seaching for help with no luck then settled myself to checking everthing step by step. The code seemed to be ok..so it had to be something else.
Anyway it is working fine now .. so quite chuffed with myself.
I was getting the wrong rates being calculated.. and thought that I had "connect" to the Australia Post DRC to get the updates.
Being a novice at this, that really threw me as I had no idea how to implement the instructions given on the DRC.
But as it turns out, when I looked further into the contribution I could see that it was set up to conect to the DRC already.(as long as your hosting allows it to connect via html.. which is should do)
The prices that were being calculated were wrong because of the Zones and also they were not adding the GST.
Make sure in your tax rates you have the 10% GST.
Initially I did not have a tax rate for Australia as I am not registered for GST and do not have to charge this tax.
But because the postage calculated includes GST within Australia.. it needs to be in the tax rates so the postage will calculate correctly.
Make sure that in Locations/Taxes>Countries set up in admin ~ that Australia is acutally in the list.
Australia ISO codes AU AUS
I also had to add the Australian Zones to Locations/Taxes>Zones as these were not in the zone list and are required for the contribution to work correctly.
Australia Australian Capital Territory ACT
Australia New South Wales NSW
Australia Northern Territory NT
Australia Queensland QLD
Australia South Australia SA
Australia Tasmania TAS
Australia Victoria VIC
Australia Western Australia WA
In Locations/Taxes>Tax Zones.. make sure you a folder for both the Australian Zones and World Zone
In Locations/Taxes>Tax Classes....remove all tax classes. Create and new tax class called GST with the description Goods & Services Tax
In Location/Taxes>Tax Rates....remove all other tax rates showing.
Create a new tax rate
Tax Class Title~ GST
Zone ~ Australian Zones
Tax Rate ~ 10.0000
Description ~GST
Priority ~ 0
Finally make sure in the Shipping Module you have
AusPOST Parcel Post ~ below is my set up. Please note I am not offering insurance.
Enable auspost
True
Dispatch Postcode
2250
Enable Insurance
False
Insurance Base Cost
4.35
Insurance Addition Cost
1.15
Insurance Unit Size
100
Maximum Weight (kg)
20
Handling Fee
0
Parcel Height (mm)
100
Parcel Width (mm)
100
Parcel Depth (mm)
100
Shipping Zone
Australian Zones
Tax Class
GST
Sort order of display.
1
Also I have
AusPOST International - AIR
Enable auspostair
True
Dispatch Postcode
2250
Enable Insurance
False
Insurance Base Cost
7.50
Insurance Addition Cost
2.00
Insurance Unit Size
100
Maximum Weight (kg)
20
Handling Fee
0
Parcel Height (mm)
100
Parcel Width (mm)
100
Parcel Depth (mm)
100
Shipping Zone
World Zones
Tax Class
--none--
Sort order of display
2
It took me a long time to work this all out..really hope this helps. Let me know if it does.
Of course back up everthing before you try making these changes.. like I said I am just a novice at this.
Cheers
Deb