You said the bag came from China, but where was the bag made in? That might make a difference? Perhaps they assumed because it shipped from China, that it was also made there? I don't know if that will make a difference as far as what they charge though?
I think anything imported from "China" has high customs fees. I only say this because I ordered a pair of Louboutins a while ago from a boutique in Germany and DHL is the courier they use. So, before ordering I wanted to see what the customs fees would be. I was asked what the total amount was, what the shoes were made of, AND also WHERE they were made. The shoes say "Made in Italy" so I got away with a lower tax, well I got away period b/c the DHL guy did not collect any taxes from me. lol
The DHL representative explained that anything coming from China and the like would have a much higher tax associated with it, perhaps 25% and UP. However, if it was Made in Italy, France, etc that it would supposedly be no more than 12%, probably 7/8% like sales tax here. The man I spoke with at DHL seemed to know what he was talking about because he got all of this information directly from a supervisor. Regardless, I think the higher fees you have been charged may be because it came from China????