Actually - reading what's on the Amazon site, it's a bit confusing. It looks like the limit applies if I send a document to my Kindle via email using 3G. However, in this case I just went to the Manage your Kindle page and delivered to my Kindle from there.
Additionally, Personal Documents show up in your Archive/Cloud. So what I did was the equivalent of selecting a book from my cloud and sending it to my Kindle.
It's not clear in the charges section that both actions are the same from a charging perspective even though there really isn't a difference between the two.