Problem- G&L Horizontal

[tsaladyga]

Can anyone explain to me the relationship from "W" axis to "P" value on a Giddings & Lewis G60F Horizontal mill?
I am trying to program this mill and the only thing I have left to understand is what the relationship is from "W" to "P"
I have copied an example here for you to see the "W" axis and the "P" value

N10M$
N20G90UVP$
N30M9$
N40GG90G40G17ZHM5M12$
N50X-40.Y-11.$
N60GW30.H$<---this is the "W" value...where did they get this value?
N70GT23M6$
N80U-14.375VP16.$<----the "z" offset?
N90GXYZ2.H23M5M9$
N100Z$
N110M$
N120UVP$
N130GG90ZM5M12$
N140X-40.Y-11.$
N150GW23.H$<---the next "W" value don't know where the relationship is.
N160GT1M6$

Tool number 23 length is a 1" drill 10" OAL. This tool is positioned in center of a flange for zeroing purposes, then the machine calls up tool #1 which is an 8" shellmill 3.960 OAL.
Does this help anyone? I really would like to understand the concept.
By the way, the machine has a Numeripath 800m control.
Thanks,
tsaladyga