Greetings! I apologize for bringing back an old thread, but can someone please double check that this function works? I tried ticking all four boxes for the U.S. in the Trans Alt & Alt Baro Calls box (I checked all the available regions, actually) and I still got inches readings in the ATIS. I double checked to verify it works in a different country (using the QNH in non-U.S. setting) and FSX shows millibars in its default ATIS scrolling message. I am using 3.10.2. I just took a flight with the intention to practice using an add-on that uses millibars so that was how I discovered the PF3 setting was not working for me. Thank you very much!