After doing the initial setup on your touchsetter, and you have machined and made necessary offset corrections to get your part to the exact dimension that is was actually programmed for, recalibrate the touch setter location by going into manual, lowering the touch setter arm, selecting parameter mode, and touching the tool to the probe. This will usually give you .0004" - .0008" better accuracy, as you are not only calibrated to a known tool, but to the way you process your parts.