[Dan Stryffeler]

Doug, I think most numbers are corrected (by SAE J1349 standards) for temperature, humidity and altitude (distance above/below sea level) because all these factors affect air density. Mine worked out as shown

Per SAE J1349 Standard
Abs. Barometric pressure 29.23"
Humidity 00.0%
Temperature 77F
Air density ratio 93.4

My SAE correction factor was 1.0487 for 29.55", 36.6% and 82.3F

At least, that's what I was told...

Dan