All I really care about is that it seems to work out that way for me. The last 3500 miles have all been single speed so I’m accustomed to the strength requirements at various cadences. Whether it’s 45 rpm up a 7.5% grade, 60 rpm up a 5% grade, 80 rpm up a 3% grade or 80 rpm into a 12 mph headwind, the power output I can manage for a 3-5 minute interval seems to fit within that 10% range. YMMV. I would not be surprised to see a wider variation for riders who don’t ride single speed.

Otto