Your mechanic overlooked something. The glaring clue is the off-center steering wheel. If nothing in the suspension system is bent the only way for the steering wheel to shift position is for the cross member to shift sideways. In the name of speed and cost, most alignment mechanics only do a quick visual inspection, then they look at the three main alignment angles, caster, camber, and toe. When parts could be bent, or when there's a handling problem even though the alignment seems fine, they also have to look closely at one of the secondary angles, "steering axis inclination" (SAI). All alignment computers measure it automatically and it will be on the printout they should have given you. A typical value could be around 28 to 32 degrees, but the exact value is not important. What is extremely important is both sides must be within 0.2 degrees of each other. If they are not, that must be corrected first, then the car must be realigned.