I have an incubator that didn't show day 1 until a day had gone by. This tells me that the day indicator is tell me how many days have gone by. Therefore, do I set lock down when it shows day 17 since 17 days have gone by and we are now on day 18 or do 18 days need to go by for lock down? They were set on 1/15/2018 and it is now 2/1/2018.