Do you have information that the couple in question were holding meetings 8-10 times per month? I did not see that in the article.
Twice a week, with about four and a half weeks in (most) months, equals 8 to 10 times per month.
I know how to use a calendar, do you? There are 4 weeks per month. Wed and Sun = 2 times per week. 4 x 2 = 8 Some months actually have a partial 5th week, hence the additional day or two. 8 + 1 = 9 and when it does include both an extra wed and sun then it would be 8 + 2 = 10. As an example last month had 4 sundays and 5 wednesdays = 9 so they would have met 9 times that month. May and June both would have given 9 meeting days. May having 5 sundays and 4 wednesdays. Actually there are a lot of months with the extra days making it more likely that they were meeting 9 times per month and not 8, with 9 being the middle of 8 - 10.
Do you need more information than that.