Amazon partnered carrier Amerex - does NOT pick up from every post code in Australia

https://sellercentral.amazon.com.au/help/hub/reference/GXP7DTQN7BSZH45X

Details the only post codes Amerex uses internally as a partnered preferred carrier. Vendors like myself who are not on list have to use non partnered carriers like Australia POST, TOLL etc. So instead of sending something from BNE to SYD at $4.99 up to 22.6kgs - it cost me nearly $50 for same distance. x 14 boxes at same weight of 16kgs. Not sure why this is their listing since the next suburb over from us is listed.