If there is an unexplained issue with ANY part of the vehicle and the issues gets to the manufacturer and the manufacturer wants the whole system, the vehicle, to be inspected by their experts, then you have to go with their experts' opinion and request. The analogy here isn't entirely accurate or relevant however. With scuba regulators, several issues with second stage performance are related to issues with the first stage and hence you have to start your troubleshooting with the entire system and not just a microscopic view. What AL experts demanded is very prudent and most likely save lots of going back and forth with unnecessary delays and shipping charges.