I wouldn't buy that one.. his in person signature is so simple it's easily forged and that looks off to me. I wouldn't be comfortable with it in my collection.
No problem, the slant of the B and the baseline of the whole signature are way off. Like I said, his signature is so simple.. on the street, in a crowd, anything is possible. This just isn't one I would be comfortable owning. There's no shortage of signatures out there. My recommendation would be to keep looking.