Embodiments disclosed herein include a method for field adjusting calibrating factors of a plurality of RF impedance matches for control of a plurality of plasma chambers. In an embodiment, the method comprises collecting and storing in a memory data from operation of the plurality of RF impedance matches, and finding a tune space for each of the plurality of RF impedance matches from the collected data. In an embodiment, the method further comprises finding adjustments to account for variability in each of the plurality of RF impedance matches, finding adjustments to variable tuning elements of the plurality of RF impedance matches to account for time varying and process related load impedances, and the method further comprises obtaining operating windows for the variable tuning elements in the plurality of RF impedance matches.