yes you would count april 3rd as day one, so 4/ 20/12 is your 18th day with them hatching on the 23rd if all goes well. i also use a lg incubator. when i go into lockdown i cut a few sponges before hand and soak them in luke warm water then add them underneath the grate, and palce them on small lids, and they have to be small to fit under the grate. also i roll paper towels in the water trays and then soak them, they stay wet the whole time and really up the humidity. using this method i hatched 22 of 31 eggs last time. once i go on lock down i don't raise the lid for anything and i keep the plugs pulled. good luck with yours
