Volvo: Alignment, alignment machines, service garages

Question
My 1999 S40 Volvo pulls to the left.  I have had it aligned by two separate and independent service garages using computer alignment machines, but to no avail.  Although both alignments put all adjustments (cast, camber and toe in) within factory settings, it still pulls to the left.  Is there something unique that is being missed?  

Answer
Robert,
Steering geometry is relatively simple and if all specs are met and it still pulls, test drive the car with the guy that did the alignment and have them go over their work. Do not overlook the possibilty that the tires can cause a pull. Swap them side to side and see what happens.