This is a very broad question because I'm continually amazed at how little I seem to know about this screen.

I need to gain an understanding of which are the hard numbers that come from stock transactions vs which are screen calculated numbers that will be recast as new transactions come in.

What are the fields that I need to pay attention to on this screen to really understand it? 

What are the best sources of information relating to Average Costing in X3 and the Average Cost Evolution screen.