You really don’t need to turn chicken eggs after about 14 days. It’s vital that you turn them early in incubation. Sumi recently posted a long list of things that turning is needed for but by two weeks all that stuff has been taken care of and turning is no longer required. It won’t do any harm, but it’s convenient to stop turning them when you up the humidity and go into lockdown. That’s the main reason the two are tied together, convenience.
The best reasons I can come up with to stop turning is that you don’t want to open the incubator the last three days because of the humidity so it’s really hard to turn by hand. You aren’t doing any good and you may do harm, not because of the turning but by opening the incubator.
If you have an automatic turner, those chicks are going to slime everything when they hatch and crawl around wet. I take my automatic turner out to make clean-up a whole lot easier, especially around the motor part.
It depends a bit on what your automatic turner looks like, but it is possible there are narrow places a chick could get a leg, wing, or neck trapped. That could injure or kill the chick, especially if that turner is still turning.
Some people think the egg being turned would mess up the chick when it is trying to get into position to hatch, especially for internal pip. I don’t think it does, but I really don’t know.
To me, it sounds like you may have some unique situation, but turning during the last few days is totally not necessary and may do some harm. So I don’t do it.