[unboggling]

Wait. I shouldn't? Why not?

Maybe I wasn't clear before. I process a bunch of books in LibraryA. Now I want to move them to LibraryB. What I have been doing to accomplish that is save them out. Then I switch libraries to LibraryB. Then add them to LibraryB. The reason I was using Save/Add sequence rather than CopyToLibrary sequence was this: I thought I was certain that saving out would update all metadata changes into both opf and internal epub metadata. I thought I was NOT certain that CopyToLibrary would do that too, so for me it was a sort of habitual hygiene kind of thing.

Now I'm beginning to realize that it would be helpful to me to question every assumption I've ever made about how things work in calibre. I have a bad habit of making unwarranted assumptions then basing work and habits on them…. Sigh….

Edit: So, does CopyToLibrary update the opf and internal epub metadata in the copies of opf and epub that end up in the copied-to library?

2nd Edit: And if so, what's the difference if any in the end result, comparing those sequences (saveout/add vs copyto).