the movement is fine. Chickens break all of the rules and hatch just fine. Besides I had 4 eggs hatch while the turner was on in the incubator once! So I label that a myth. My experience is they co raise the chicks.
xs2 - I saw my broodies move their eggs even up until and after they were pipping. The thing with the bator is more that you shouldn't be opening the lid because it reduces temps & humidity levels. I've read plenty of posts where they forgot to turn off the turner and still got hatches - there the risk is the chick will get caught in the turner as it rotates and not be able to get out of it.