Thanks for your feedback @AlphaDogCycling!
It is important to note that the offset value does not need to be the same every time for the calibration to be successful. As long as the calibration goes through, your power meter was successfully calibrated; there are no suspect calibrations.
The offset value can change in response to a variety of environmental factors, most notably temperature. If you are dealing with varying temperatures (change in season, indoor/outdoor, etc) then you would see different offset values upon calibration, but that does not affect the validity of the calibration itself.
By tracking and recording offset values in this manner, it would likely lead to misinformation and confusion when the reality is, you really only need to know if the calibration was successful or not 
.