I've found that a very, very low gear 26/32 or 26/36 I can spin @85 or so on >5% gradients (180-200 bkool watts). Take that to a 36/32 or 36/36 and I'm down to 70-75 (190-210 bkool watts). Speed/power turns out to be very similar. I can hold the low spin gear easier, but put out a little more power easier in the higher gear. But I tend to burn out quicker in the higher gear. It's just finding that sweet spot of the 2.
Higher you can sustain the spin, less load on the legs and more on the heart and lungs, which can recover in a very short time. Your results mirror mine. Watts are virtually the same for a easier gear with higher cadence=less fatigue.