Hero XP: XP Gain Formula

What is it? How do the gameplay constants work into a forumla for the amount of XP that a hero gets? I'm talking aobut the gamplay constants in the advanced menu labeled:

Hero XP Gain: Hero, Constant Factor
Hero XP Gain: Hero, Level Factor
Hero XP Gain: Hero, Previous Value Factor
Hero XP Gain: Hero, Table

I know that I can use the table to set my experience right but that is a waste of time and space in a level 250 or above map... Please help me

XP gain = CF + level*LF + previous value*PVF

Table only needs one value, for level one, to give it a previous value factor for level 2.