It's my opinion that you are pissing up a rope my friend. If the probe returns a diameter of .3000" on a .3000" master tool, then the probe is not the issue.
PERIOD.
You are finding that machining is not automatic. You have recieved many replies from many very experienced machinsts to disregaurd the probe results (or don't probe diameter at all, which is what I ended up doing when I went down this exact same road many years ago) and make your parts correct-to-size with wear offsets. This is how it's done in any shop that isn't running a $40,000+ presetter (and they still have to tweak stuff to size). Wear offsets are used every day around the world. You should use them too.