They needed Vettel to help gap Alonso. I think Webber actually ended up running longer than they would've done since Vettel had to push to help himself gap Alonso once they realized they were going to do a drive-through, and Alonso was subsequently allowed to drive (maybe) faster than he otherwise would have. If the strategy played out the way it should, Webber probably would have pitted earlier, and Vettel would have bolted a few laps before Webber's stop so Webber will be between the two.
University of Toronto Formula SAE Alumni 2003-2007
Formula Student Championship 2003, 2005, 2006
www.fsae.utoronto.ca