To illustrate this and @jonathanwaddell comment, in the other cat B race the winner pulled only 3.3 wkg avg (way below the 3.9 max)
What you’ll notice from the top 7 finishers is the higher variability index than the rest of the field - the top finishers drafted drafted drafted all race and saved their energy to hammer the start, inclines and finish. They only need to do enough to not lose the draft of the front group.