I think once a reply is posted, you can’t edit a post.
If she is charging that much for shipping for those reasons, there is no need to be rude to anyone that asks :/ She could just politely explain it, that’s all. Or even mention it in the auction. I think everyone would appreciate her wanting to make sure the item gets to the buyer in one piece! And if I had the money and didn’t have that piece, I would bid knowing she’s willing to follow the “correct” way to ship the item.
And yes, UPS is a terrible place to buy shipping items. They charge something like $7 for an empty box, ugh.