You counted correctly the 1st time. You don't count the day you put them in (Day 0). Your 21st day will be Oct 28th.
I'm not really sure what happened with my countdown. I checked here and saw that I put them in the incubator on the 7th. That means the 21st day is October 27th. I'm not sure why I thought it was the 28th instead, and I'm not sure how to interpret what the incubator says is left since it counts...
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