BT, generally when I see a 21 day notice period, it refers to calendar days (3 full weeks), not business days.  When you see business days, when it's 10 or more, you almost exclusively see a multiple of 5 employed, and over 20, a multiple of 10.

I was a little disappointed we didn't get an NR after market close today, but I agree, tomorrow would be the day.  Trading will be light in the US on Friday, as many will be turning the 4th into a 4 day weekend

For our current purposes, what the news is, is about 1,000 times more important than when.