I'm somewhat glad that you have come to the same conclusions as me in as much as the rules are fine.
I can confirm that in the process of creating the package I have been tweaking the package many times, but each time I amend it I use the Delete option when I republish. Believe it or not over the last four days during troubleshooting I'm up to version 32!
From what you have said it could be a case that PM hasn't fully deleted a revision of the package.
How can fully remove all instances of the package? Is there a cleanup tool. I'm quite happy to rebuild the package and start at version 1 again.
Thanks again for your help.