Thanks for the replies.
A couple of things:
1) for the moment, let's put aside whether this makes sense; I'll change the question: suppose a change could be made such that one would use 177 watts rather than 181 watts when cycling from point a to point b on a 2.5% grade in 5 minutes. Is the difference in watts significant/meaningful? Were you to get this difference, would you think it was a big deal, a somewhat big deal or no big deal at all?
2) Couldn't pedaling/stroke efficiency affect power requirement in watts? That is, perhaps, relatively speaking, my pedaling stroke was smoother in the second run. Wouldn't that affect energy requirements? Think about it. Consider 2 cyclists, KO and KI. KO pedals with his knees pointing out to the side (i.e., pretty inefficient) and KI pedals with his knees straight up and down over the pedals (i.e., pretty efficient -- if you prefer to say over the crank-arms, that's fine too...but, let's assume clearly that KI pedals with more efficiency). So, they are riding together from point A to point B. They are each in the same gear; they are each pedaling with the same rpm/cadence; they ride next to each other the whole way from point A to point B such that their distance covered is the same and their average speed is the same (and again, the average cadence was the same). Do you believe that KO -- who again is pedaling with a less efficient stroke technique -- had to generate more energy than KI to cover the same distance in the same length of time with the same cadence? If you answered yes
, would you please indicate whether 177 watts vs 181 watts in my scenario was material, i.e., would you care if you were able to realize this change in your energy use?