UPS and FedEx will add a broker fee (for handling the paperwork) even when there is no duty owed on the imported goods. Whenever possible, I have the goods shipped by the postal service (Royal Mail etc.). The US Postal Service handles the delivery on our side, and they have never charged me a broker fee only the actual duties owed. Hope this helps.
Returning to the topic of possible duty fees on Aldens shipped from the EU (Frans Boone) to the US by UPS: I did end up getting an invoice for duty and brokerage fees, though as far as I can tell this is in error (https://help.cbp.gov/app/answers/detail/a_id/375/~/duty-on-u.s.-made-goods-returning-to-the-u.s.). What's unfortunate is that I have now had to call and leave a message to discuss this with someone at UPS, which is a waste of my time.
It looks as if Frans Boone did not mark USA made goods on the invoice and actually has language saying that the items are of EU origin unless otherwise noted. So that is likely the problem. I suppose anyone ordering Aldens from them should emphasize that the invoice needs to be clearly marked: USA made goods.
Addendum: It looks as if there's also a form that's supposed to be filled out by the importer: http://forms.cbp.gov/pdf/CBP_Form_3311.pdf. Not sure if that means me, or if UPS might have filled this out (and I'm sure charged me $6.50 to do it, which may well be fair enough).