> They know they're going to have to do the extra work, why not take that into account on the base price?

There's the option of doing it yourself or have some third party doing it, though you usually still end up paying some fee to the express company.

A lot of business customers do that, at least here, especially if they got goods with duties where they might not be confident in the goods classification[1] done by the express company, or if they have exemptions.

Though as I mentioned earlier, I do agree there's too little transparency here, and that they're taking advantage of it. I suspect the only way they'll improve is if customers start voting with their wallet.

[1]: https://en.wikipedia.org/wiki/Harmonized_System#Classificati...