6 Week Absence After Applying for Citizenship

Just wondering about the 6 week rule on absences after applying for Citizenship. I thought I saw previously on the forum that it only counts full dates outside the country, and not the date you depart/return. Does anyone know if this is the case or no? E.G fly out Monday return Sunday would that count as 7 days or 5?

My husband has applied for citizenship and is currently on 39 days this year (if we count depart and return days) as he had 2 work trips this year plus a long holiday after covid. We want to book a trip early next year but since nobody is really sure if a year is Jan-Dec or a rolling 12 month period or both, we want to keep under 42 days in a rolling 12 month period too. If it doesn't include departure/arrival days then we are fine but if it does then we cant go anywhere I guess till later next year.

It doesn’t include departure and arrival date.

Perfect, thank you That makes it low enough then.