You only pay customs duties for the cost of the products you have bought in AUD. So for example, if you were to import clothing, which had costs you $1500AUD, according to Australian Customs, you pay 17.5% of the $1500AUD. This is the FOB quote (normally), you only pay the 10% GST for freight, IF YOU WERE TO USE YOUR FREIGHT ACCOUNT HERE N AUSTRALIA AS IT CARRIES A GST PORTION. If you were to be importing on a CIF agreement with your supplier (Cost, Insurance and Freight), then you just pay for the FOB portion of the CIF. I hope that answers your question.