Saying 'neither' leads me to believe that you know what these settings do. Can you answer and what they do then instead of basically saying 'no'?
That's because the difficulty is SCALED. The job/profession/skill difficulty is increased
*or decreased by the same FACTOR as whatever age setting you choose. How can you not understand this? Honestly, if you can't understand how things are generally scaled you are too stupid to use AM.
*Edited to make a more accurate statement.