Moved my cleats forward 1cm yesterday and just noticed that I set a 10-15 second power
PR, at the end of a 2 hour, 0.80 IF fast ride. And that was riding with -20 TSB.
I'm deeply suspicious of any magic bullet type improvements or fixes, but those numbers certainly caught my eye!
[edit] I didn't move the saddle at all. Thinking about this, by moving the cleats and not the saddle, I suppose I effectively lowered the saddle height and moved it back. I don't think this affects the high end power gains as that was out of the saddle, but it does mean that everything about the fit is sort of in flux.