Please see SAE J443 Section 7 below is basically a copy of what it says. Each intensity verification location has it's own unique saturation point. Run all the intensity verifications to longest saturation time of the group of holders, record your results. These resulting numbers are now your "target arc height". Now when you are in production all you do is run the holders to the "target arc height" time and compare them with your original "target arc height" results. As long as these numbers are within +/-.0015" you are good to go. Important! The resultant arc height readings do not have to be within the intensity tolerance band since the single verification time at a given location may be substantially less than or greater than T (saturation point)