Something ain't right here, Talldog. Over a six stage race with a "mean uphill time trial" they measured a "peak" power of 390 W??? I'm an engineer, I need to see their definition of "peak". To an engineer "peak" means the absolute maximum observed value. Surely these world class cyclists hit peaks over 390 W in sprints and climbs. Based on the table at the end of the material you quoted I might barely qualify as a "fit guy" class cyclist and I hit peaks over 390 W as I struggle to climb the cluster of 20+% but mercifully short grades on the trail by me.

My power meter is not the most highly respected unit on the market, it is a Polar CS600X. Yet some professional mechanical engineers who have played with them claim they are reasonably accurate. My results match the "fit guy" curve quite well so I imagine it is within 10 or 20%. Even that curve predicts that a lowly fit guy cyclist will hit more than 390 W peaks in a race....

Ken