They can't be expensive, you can ask of course, but they've got to warranty their work so if they recommend it and it's not too much then I should just let them if I were you. You are testing at DC. The resistors will be running at high pulse rates which you most likely cannot test at.At the mercy of the IP Calibration shop, they also want to replace the correction resistors which i've tested over n over to be good.... sigh.