Is anyone here familiar with David Blaine's signature (or signing habits)?

I was asked by a friend if I would help her sell a David Blaine autograph, and after doing a little bit of research just now, I'm trying to figure out if might be special?

David signed it with his "Split Spade" (db) in the middle of his signature (for the last "d" in his first name, and the "B" in his last name). Does anyone know if this was common? After looking around some, I can't find other examples like this even though he seems to be a prolific signer. This would've been signed in 2009 or 2010, so I didn't know if maybe it's just the way he used to sign since most of the examples I'm seeing are more recent.