As I traded e-mails with Brotherton, he turned me on to this post.
I think the recommendation for use of the spreader bar comes from the companies assuming that the front suspension will have some wear. I have used the spreader and I have done alignments without. I think that the best alignments are done when all of the components under the suspension have no wear.
I replace all worn components and will not perform an alignment unless I am allowed to do it MY way.
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS