Originally Posted by
pakossa
this might indicate that your fit isn't quite in the ballpark. For instance, say your fore/aft is off by 20mm. If you adjust it by 5 mm, you're still off by 15 mm, so there probably won't be much difference. Whereas, if you're off by only 5 - 10 mm, you should notice a difference. (this assumes saddle height or bar positioning isn't significantly off . . . One of those could be the reason, too.)
lol
I've actually got a Wahoo Kickr Bike, so it's very easy to do a full sweep of saddle fore/aft position, which I've done several times. It also simulates gradients up to 20%. My own conclusion was that saddle fore-aft position is not super-critical. It's more about finding a well balanced riding position rather than variation in power output. If you are seeing literally 100% power variation between 5 mm positions, then maybe some of your leg muscles are missing?