Again, as I've stated previously, along with the others having this problem, it cannot be user calibrated because it's only off center points having the issue and any calibration gets applied to all focus points, throwing the center point(s) out. Neither in camera AFMA nor the sigma dock can fix this issue, and sigma service has stated that they cannot fix it either until the sigma corporation finishes writing the software necessary to do it with (note: they said it's software to be used at the service centers, so it will still not be a user serviceable issue). At least it sounds like they are working towards making it fixable, god knows how long that will take.
Interesting. I just came to the forum to post exactly the same issue with the 35A I have. My first two copies were so far off that I had to return them; I used both FoCal and the dock to calibrate them, but they couldn't even focus properly with center point and a focus target with camera mounted on a tripod.
My third copy is much better. I was able to use the dock along with FoCal to get it consistent using center-point focus, though it did need large adjustments (something like +9, +5, +4, +3 IIRC).
However, when using outer focus points, it's ridiculously off. It will focus on an object a foot in front of what I'm actually focusing on—it's not even close. For example, I took some shots of my daughter sitting on the couch holding a friend's newborn on her lap. Even though I was focusing on my daughter's eyes (with a cross-focus point a little left and above center), the lens decided to focus on the baby's face... which was a good 8-10" in front of my daughter's eyes, and at least 12-16" below.
Like everyone else, I am blown away by the sharpness and clarity of the 35A when it hits. But being forced to use the center focus point in order to get those results is a dealbreaker. 90% of the pictures I take are of people that are moving. Focus and recompose is not an option.
So I am selling my 35A and buying a 35 IS. And as excited as I was about the 50A, I'm going to pass on that as well. Still hoping Canon will come out with a 50 IS or revamped 50/1.4. In the meantime, may just skip up to the 85/1.8 and have a 35/85 combo with two small, compact lenses. This appeals to me because my main workhorses are the 24-70 II and the 70–200 IS.