You make a lot of false assumptions:
Production variations and tolerances can account for small discrepancies from published specs, but the table in the quote you cited was off by more than 3 orders of magnitude (1600x).
My statements did not exclude the possibility of confirmation bias and I certainly believe that is a factor. If a reviewer is evaluating a piece of equipment and the specs are fairly normal or at least reasonable, there should be no reason to doubt them or scrutinize more carefully. In the case of DD2, a W&F spec of 1PPM begs for additional scrutiny, confirmation bias be damned.
I have no reason to believe that either table was not representative of a typical production unit. While DD2 was not new, I saw no evidence of abuse or neglect or any other reason why it should perform as it did other than what I perceive as a design flaw (using an iron core motor for DD). DD1 was purchased new from an authorized dealer and the packaging was substantial and bore no signs of distress or mishandling in shipping. I sold it at a discount after the evaluation was complete and did not hear of any complaints from the buyer which would only further support my hypothesis. You have no first hand knowledge of the units yet you speculate (assume?) that the poor measurements are due to transportation or environment?
