This is a time proven step that can save you much time.  Setting up your calibration gear comes later in the process.  Too often, you can begin a calibration only to discover an obvious problem that turns the calibration into a service call.  Make sure the system is ready to be calibrated before you painstakingly set up you microphone kit.  It’s not a bad idea to use this process before agreeing to calibrate or to augment your service calls.