Mea culpa: I had, in fact, entirely failed to notice that element in the Amazon UI.

I can't imagine why:



I mean, aside from the fact that it's tiny grey type on a blue-grey background right next to big bold red type, in a small corner of a big, cluttered page.

I remain baffled why, especially if they're not trying to hide the information, they don't break it out in the checkout itemization. But thank you, at least in the future I'll know where to look for the info.