This is a very useful script. I've been using your batch-add "performance-of" relationships script, but when I'm working from a release, it's tedious locating all of the recordings on the Recordings pages. This works much better; I can locate all of the works from the release page that I'm working with.
Just a suggestion - put a note in somewhere about checking the "Edit works" box. It took me a while to spot it; until it's checked, it looks like the script isn't working.