Good guys can have a dyno stack that is out of calibration. If they know they are not such good guys. Average barometric pressure in the area is about 29.00. The dry 80°F day of the dyno it was baro 27.1" HG? No sense to even get down to the correction factor discussion when the stack is out of calibration. So your suspicions were correct, this is a happy dyno.
If you are in the area look up Bob Thoma, Razorback Performance, Eau Claire, WI and have him do a pull, if interested. If not consider taking 10% off the numbers you received for a ball park of what it will do on a calibrated dyno with the latest software corrected to SAE factor.