@Jim L,
Of course you're right, variables such as ambient temperature and thermal stability are essential for this type of measurement.
A colleague Jeff from CN showed in one of his threads DPAC measurements performed during the optics' coming to a state of thermal equilibrium with the environment.
SA correction changes for all colors over time were significant!
Scott, who studied the first of the two SVX127D samples, says nothing about thermal stabilization time.
Moshen also makes no mention of it.
However, if it was about the lack of a fixed temperature, the correction in red would also be worse, which is not the case.
The position of a lens of this size doesn't matter at all. If this were the case, we would see astigmatism or coma depending
on the height above the horizon of the observed object. And that's not what happens. This would be a significant design flaw of the lens cell.
Now I will refer to the internal standards and the ZYGO test. As I wrote earlier, perfect tuning for the red light line does not guarantee
the same for the other lines (green and blue). With red only, they were able to eliminate SA for that color (red only) and coma, astigmatism, zones, and turned edges for all colors (red, green, and blue).
To sum up, the authors of the DPAC tests should be asked about the thermal stabilization time of the tested telescopes.
Each measurement of this type requires diligence, honesty, certain knowledge and significant time, above all, in the interpretation of the results.
I also don't like how excessive optimism and excitement about the topic affect the interpretation of the results.
I've often noticed this in some threads where AOS was used. However, anyone who has ronchigrams available
on the forum can repeat the analysis himself and check whether the author of the results has not suffered too much fantasy. I do just that.