Keep that humidity UP during lock down and hatching.
If the humidity is too low, it can dry out the membrane and "shrink wrap" the chick inside. If it's too high, you run the risk of physical defects.
It needs to be between 60-70% during lock down... Throw in a warm, wet sponge or rag to bring it up if needed.
Give them a little more time. Do you see any rocking? Do you hear any peeping?
Edit to add: You must also take into account your personal weather situation. For example, it's been raining and warm here non-stop for a week. I probably would NOT add any humidity sponged, because the ambient humidity is something like 99%. It's important to know the humidity outside, inside, and in the incubator... especially if you're incubating in a place that has a lot of in-and-out traffic, which can effect local humidity and temperature in that area of your house. I have incubated twice on my kitchen table by the patio door. I saw no difference in my own hatching rate (hatched 11 out of 15 quail, eight out of nine chickens), but your mileage may vary.
There are A LOT of things to take into consideration, and it sounds much more complicated than I feel it actually is.

You'll get the hang of it!
MrsB