Looks like the PO managers advice was not quite right. The tiers are 10% for minimum 5 parcels per week, 12.5 % for minimum 10 parcels per week and 15% for minimum 20 parcels per week.

This information came from the AP mypost website.

While it looks like it might take awhile to sort out exactly how it all works, it actually sounds pretty good and definately worth a look.

search auspost.com.au/mypostbusiness for further info.