Alms:

I've worked on high end Italian bikes that had all the nice, thick branded dropouts with chain adjuster screws, and to align the rear axle and center the wheel, I had to have the screws adjusted more than 1mm different in depth. It didn't give me a real high confidence in those frames. And at our shop, we would whip out the alignment tools and clamp them onto the dropouts, and pulling back all the way to the ends didn't quite line up, but pushing the clamping point forward gave much better wheel alignment, and effectively shortened the chainstay too. So it is quite acceptable and the bike rode fine.