Hi Tom,

Historically, we have used the s.g. value for Douglas Fir specified for the “Interior West” region of the U.S. as determined by the USDA Center for Wood Anatomy Research.  Over the years new data has come out for other wood species, and in a recent effort to make our meters more up to date with the latest research, we adjusted some s.g. values for some species accordingly. 

During that process, we decided to take into account the specified values of s.g. for Douglas Fir in other regional areas.  They are very close to one another, so instead of injecting confusion by specifying multiple regional values, we averaged the separate regional values together, and that is how the 0.48 value for s.g. is calculated. 

If you view the reference listed below, you will see the separate regional areas listed with their respective s.g. values.  Even so, to be even more accurate, one can always adjust their s.g. setting in their meter to more appropriately reflect their regional and/or log diet actual s.g.

I am also going to pass your post along to manufacturing, so they can take appropriate steps to address your concerns as well.  I hope this helps clarify the situation for you and others, and thank you for your diligence!

Reference:
http://www.fpl.fs.fed.us/documnts/TechSheets/SoftwoodNA/htmlDocs/pseudomenziesii.html

Best Regards,
Tim