On latest two versions of Photoshop, there's a problem with pre-saved XMP-files. They appear in alphabethical order in Library - in XMP -subfolder, but when you open the File Info, the list is in mixed order. In other words, a big mess.
Didn't find any solution for this. It's not a big problem, but really annoyning when you're fixing loads of pictures with different metadata.
Fixing or help needed:)!
Remote support didn't find any solution and thought that it's a bug.