If I use your Rho and Crr, I get 408 watts. I use a 2% drive train loss and 173 pounds of rider weight plus equipment. My tested CdA at the indoor track by ERO with a Dolan DF3, a double lenticular disc and Shimano Pro aero pursuit bars, UK quasi custom skin suit and Giro Selector aero helmet and a perfectly turtled head was .2375. It is questionable whether I could get that low of a CdA on my Cervelo TT bike with a disc /trispoke setup at Fiesta. Also, even with a great glue job and perfectly round Vitorria Corsa EVO CS tubulars, I think the Crr would be higher on Fiesta and the road surface is pretty good. I could use R Chung's method and measure Crr and plot a curve of Crr v Tire Pressure for my tire setup. I think you know that professional teams optimize tire pressure for the road surface for TTs in grand tours.
It is very clear that all this detail matters for this discipline. Even at 400 watts of power, 10 watts matters...a lot.