Thanks everyone for answering. I guess I still don't have a clear answer to may real question.
Is there some reason that manufactures very often specify a tongue weight capacity of 10% the max towing capacity regardless of GVWR, GAWRFR, or GAWRR? I was even looking a a hitch component manufacturer the other day and on their website and they said to determine the tongue weight by calculating 10% GTWR.
This conflicts with a 10-15% ideal weight on the hitch, and is basically forces the towing capacity to be lower than specified.
In addition in the forums I keep seeing allowed tongue weight determined by taking GAWRR and subtracting the rear axle weight from a CAT scale. When people ask questions about tongue weight the answer seems to often neglect any reference to the tongue weight capacity specified by the manufacturer.