I have one 14k GN flatdeck trailer with 7k axles. The axles are 5/8" out of parallel axles however when measure at the end of the axle stubs everything is within tol. This trailer has some 48k miles/8 years on the tires with no wear issues of the tire or suspension.
I also have a 10k GVWR car hauler that had one tire wear issues. The alignment shop found the axles were parallel but one axle stub was probably not welded inline with the axle tube at the time of mfg. The shop bent the end of the tube so the axle stub would track the front axle.
I'm more concerned with the axle stub location/angle as it controls the direction of that wheels travel.