when you get into the -extended settings- your basically adjusting the way the radio recieves and monitors the tx's
some settings are for detecting the beginning and ending of a TX,others are for more detailed set up of the digital trunking,nac's(network access codes) ect,,
multi site modes,as well as mixed mode adjustments.
true,for the newer user they can be left most of the time.
but as you get more into the -hobby- you may find yourself in an ongoing quest to try to tweak the RX of your chosen systems for fun or just to see what teh diff is..
if your using an app like win500-arc500 ect have fun playing around,,just save your current file and youll have a solid back up for when you need it!