Your understanding of the Change-Id footer sounds like it matches mine.

I’d note that it works that way presently, but the teams behind git, gerrit, jj-vcs, and a couple of other relevant stakeholders have an email thread going in which, from what I understand, they discuss standardizing on the approach taken by jj-vcs:

https://lore.kernel.org/git/CAESOdVAspxUJKGAA58i0tvks4ZOfoGf...