The 'Duties' section is the tariff, that does nothing to explain the shipping price.
As a comparison I just clicked Shiori's b-day since that's the first other one that I saw on the shop,
View attachment 99035
$46 is still an excessively high shipping price, but that's nothing compared to $72 for an $80 set with similarly sized products.
Edit: To clarify about the suggestion that it's the shipping company upping prices to take advantage of confusion, I still think that doesn't explain it because of the difference between the charges on these two sets.