Hi, welcome to the forum! Glad you joined!
I agree with Yardmom, you did no harm. You do want to turn them but starting a day late will not hurt them.
I do not know which incubator you have or how you prepare it for lockdown. There are a lot of different models on the market and they can be quite different. Knowing what you are working with makes answering some of these questions easier.
I know I'm an old fart and like to control some of these things myself instead of relying on things that may not have been programmed correctly and cannot respond to actual conditions. I'm one of those people that says technology is great when it works but don't always trust it to work as it should. Sometimes that is operator error.
I don't know what effects setting that timer actually has. Eggs don't always hatch at exactly 21 days. For many different reasons they might be as much as 2 days early or late. Lockdown is after 18 days of incubation so that is not affected but actual hatch day that can vary. That is why lockdown is after 18 days so you can lockdown before the early ones hatch. There was a recent post on here where an incubator shut down on the pre-set 21 days but the hatch was not over. It was not good. I do not know which model of incubator that was.
For me lockdown includes taking the turner out, increasing the humidity, and candling the eggs. I keep track by a caveman way, using a calendar. I can count to 18 without having to use electronics. I can trust myself to get it right.
If you can tell us what incubator you are using, either make and model or a link so we can find it online we might be better able to advise you, especially if someone has used that exact incubator. But without them knowing which incubator you are using I would not trust what anyone says. There are too many differences in the different incubators.
