Same here, I was really surprised. It was a nice change of pace though. Maybe it was just the euphoria of the show, but I thought they did a really good job.
I love this band but this didn't sound all that swell. Wasn't terrible, I just feel like the song didn't translate well with AL4W's sound.
I think it would have translated better with their sound in a recorded track. He has a great voice for it, but it's hard to produce the same sound in the middle of a show.