The solution is right here where you answered your own question to pinpointing your problem...................
Bill
The dealer should have aligned it when they changed the rack arm.....but as mentioned....was it done correctly?
An good argument for buying the true laser system...most dealers require you to drop off the vehicle for any service..That usually means it will sit there for many days untouched. Once you buy your SS you go to the bottom of the list behind all the new vehicles being prepped for delivery...and others in for repairs ahead of you.