I have placed the new version of the model on O:\_Dropbox\modelgriffith3.xls

The second function works off the "Skew4" tab, and the name of the function 
is "calcskew2"
The inputs to the calcskew2 function are the same, except for "a" and "b", 
which are now
"anew" and "bnew".

Regards,

Hector