You’re such a lovely helpful person Sons & Daughters ….
Do you buy much from overseas charitable organisations? Probably not but I can tell you that there is NO alternative to your assumption as you might of absorbed in while reading.  Oh & by the way any company who charges an import tariff on goods that they are handling & are delivered in Australia can be fined or made to stand with our governing bodies review board if they are found to have extortionate dealings within our borders. This is a government judicial agency issue!!