http://www.autoshop101.com/forms/h63.pdf
Details as to how they factor it into the feedback control I do not know. But I'm certain there's a calculated flow rate and specification for the PCV valve on each engine. PCV flow at X inHg vacuum is a known constant for every valve. I don't think that's information anyone is going to be able to readily come by, though.
Late,
Trav