I've been cycling my whole adult life 34yo and do some serious K's in the mountains here in France. Had never had a bike fit, but recently got one thrown in with a bike bought from a fancy French bike shop (Dvélos) - they ****ed it up massively. The guy just assumed I was clueless - and put my saddle at least 2 cm too low. when I said that it wasn't right on the turbo, he scratched his head and started to **** about with my cleats and moved them forward as far as possible - I let him do his thing to see what the result would be and, despite repeatedly telling him it's not quite right, he just insisted that too many people ride with their saddles too high and that I need to drop my heels more - dumb as ****!

Went for a 40k ride like that just to see if it would magically start to feel OK - never did. I got a bit of knee ache, that's all!
Today, I put my saddle back up and cleats back where they were before and boom! the power was back on, no hip movement. Did the 0.883 thing just to see and it's about spot on.

Bike fits are for absolute beginners only!