Okay, finally got to this, and installed your .b5. License key now inputs fine on root site, and subsite where it’s activated looks good. One odd thing is that you need to deactivate it on root site before you can delete it via network admin; i.e., delete link does not appear on network admin until deactivated from root site. (Of course, I’ve only had to do this to manually update, but hopefully auto update will work now.)
Thanks for your quick development effort!