thanks . I actually found a great description in herb adams book chassis engineering. chapter 1 ,lol deals with this. basically, cornering force increases with vertical load, but not as fast as vertical load.
so . if 500lbs of vertical load is 700lbs of traction then cornering efficiency is 700/500or 1.4
if load increases to 1000lbs and traction increases to 1000lbs then cornering efficiency is lowered to 1.0 even though traction did increase.(1000/1000)
finally, say you increase vertical load to 1500lbs but traction only increases to 1250 then you have again increased traction but decreased cornering efficiency
1250/1500 or .83