Who was doing the alignment?
If it wasn't a MB specialist /dealer you might find that they need to RTFM... I'm sure this isn't always the case but for some of them there new fangled laser guided more expensive than the space shuttle machines they need to "sweep" the wheels (what ever that means - I haven't a clue what it means I just picked it up from some guy on the forum some time ago - I'll try and dig out the post)
EDIT =>
http://www.peachparts.com/shopforum/2716547-post21.html
This post