I should have been clearer in my post that I did make the new booking before I canceled the old one. So it was not a "cancel and rebook", it was a "book again then cancel original". It was clawed back. It posted today.

Maybe if you wait for the new purchase to post to the account before canceling the original it would work? I don't know. I am just hoping that this third booking, which was made after I saw the meter reset to 0/250, properly triggers the credit again. I will leave it to others to play it risky and figure out the exact behaviors.