AP: Flight Level vs Altitude

HelloFirst I would say that after 3 days of discovering Madame Jetstream 41, I am very pleased and more and more eager to understand and being able to fly her correctly on IVAO network!!!Yesterday evening was my first flight under FMS/LNAV control (and the famous EFB from Aivlasoft), and I got a strange behavior with the autopilot:After passing the transition Altitude while climbing I changed the altimeter setting to 1013mb, then the autopilot altitude preset seems to remain working with local altimeter setting??!! ( I have had to stop her manually to climb over FL160...)I noticed that when at 3000 ft after the descent, as I have forgotten to set the local altimeter setting, I was not then at 3000ft level flight until I switch to the local altimeter setting...Did I do something wrong? and how then to pre select FL160 for instance in the autopilot?kind regardsPascal