Thanks for the tag @momcqueen!
Hi @splattii - this is an interesting situation. While the Global Shipping Program does include fees unrelated to customs/duties having to do with the preparation of the item for international shipment, I'm not certain how that interacts in a Best Offer scenario.
Everything that I have on this currently reinforces that all information provided is an estimate until the item is actually paid for (for reasons other posters point out), but I'm happy to get official clarification from the teams involved. It will take some time however, as many teams are out for the rest of the year - oh to have that much vacation saved! 😛
Tyler,