Safari Auto-Fill won't enter other peoples' addresses

If I'm in Safari on my Mac and want to fill out a "Ship to" form with someone else's address (not mine), Auto-Fill does not prompt anyone else's address but my own. In Safari preferences I have "Using information from my Contacts" checked ... and it does offer to enter my address information, but no one else's.

Am I doing something wrong?

Using Sequoia 15.4.1 and Safari 18.4

(Note using iOS, this works. When I get to an address page, iOS lets me hit "AutoFill Contact", then gives me "Other Contact" as an option.)