I have a shop that only sells different varieties of the same general type of merchandise. Let's say cell phone accessories for example.
Right now you can pre-fill the customs form for all international shipments, and that's fantastic. BUT if you have a customer that has ordered more than 5 items it won't fit on the USPS customs form 4x6 label. It wants to print "cell phone accessories" 12 times if they've ordered 12 items.
So for every larger international order we have to go in and override the customs form. It doesn't make sense that you'd let people prefill it, but then have to go back and correct the information that was provided correctly. It seems like a bug to me. We've always just written "cell phone accessories" on the form.