You may be able to see for yourself if you have an AFMA issue by setting the aperture to f/2.8 and running it through the AFMA tests. The DYI part at the bottom. When testing a new lens, I often set up something similar, but even simpler. My countertops have a pattern to them and I put a high contrast box with good lighting on them. I then shoot 5-10 shots with camera parallel to the box and the center AF point at the same point of the box (tripod mounted would help) and I see if the focal plane is in front or behind where it should be. I also sometimes see the focal plane bouncing around.