Testing one clincher on a particular road and claiming that PSI as optimum for all tires is a fairly thin premise.

My comment on "needing" higher pressures for tubulars was relating to achieving the best crr midpoint (amorphous though that may be) compared to clinchers. Many folks who are new to tubulars pump them to 110 then wonder why they feel slow and dead. My experience, which dovetails with every tubular test I've seen, shows tubulars need, on average, a higher pressure for best performance than, on average, clinchers under the same conditions.

Zipp does their recommended PSI based on rider weight and type of surface for their tubulars, they generally recommend a PSI over the maximum rating for most clinchers (110-115) for all but the lightest riders. And I've seen one fairly extensive test where there was an 8% decrease in crr between 120-140 on one tubular, this downward trend continued as pressure was increased.

I've played this saw before, but there's also a speed issue to be considered. Running a tire over a rough surface on a climb at 7 MPH will likely produce a different crr than running the same tire over the same surface at 30 MPH. And there were also some fairly large changes in crr between new and used tires, type of glue, number of layers, Etc.

BTW, I've heard good things about the Botrager, had my Records fall apart, never ran the Crono's and have had good experience with the newest Zipp Tangente (the older ones were a bit lumpy).

And the BTR test had the (old) Zipps within .00002 crr of the Records and a watt of the best tire they tested at 120 PSI.

Which leaves us back to a best guess and a lot of variables. Heck, I even won a number of races on the much maligned Tufo brand.