Simon, I would say 10cm at 1m is way off.
I always tune my cameras as good as it gets. Usually so that on 50mm lens the 1m mark is within DOF at f2.
Fine tuning the RF is an iterative process. First calibrate infinity, then the close focus, then infinity again etc. until you're satisfied with it.
Move the "RF sensor" little at a time
. Almost so little you won't notice it's moved. Be warned that if you push too much, it will do a kind of quantum leap, and you can start over again.