[wxqc] Barometer readings suspect

[Jim]

I'm looking for some insight here on my barometer readings. 
My "Quality spread Distribution Page"  is at

http://weather.gladstonefamily.net/cgi-bin/wxqual.pl?site=C4808

The barometric pressure error appears troublesome. I have used the Davis 
Vantage Pro2 weather station as it came from Davis.   Should I be adding 
an offset to the barometric numbers?

If so, should this be done within the VP2 console or, in my case, the 
VWS software??
I appreciate any insight here.

thanks
jim