You are right, and most of time I work in low light. And as you say, this is the state of technology, with consistency not 100% and autofocus being an imperfect technology. Before having a DSRL and having a compact camera with mostly 100% focused images where i wanted, I thought DSLR would be better with autofocusing and always 100% focusing correctly. But in DSLR I have now F1.8 lenses (with a lot of less DOF) and phase detection AF having more errors and imperfections that contrast detection AF but being faster.
If I remember well, the working distance for the images of test is 0.5m measured from the focal plane of the camera.
My usual working distance is between 1 and 3 meters for people and more (could be 10meters) for far shots (ie streets, etc).