Is a 5 day week vs a 4 day week make a difference for Cycle Time

[kelly jean dennis]

Asked a colleague to  expand on what differences they saw to the cumulative time chart results when they changed their working days from Mon-Fri to Mon-Thursday?  They commented as follows: 

Our team largely works four 10-hour days, Monday-Thursday. The cycle time average for our last three-month deployment cycle using Mon-Thurs came out 2d 9h. With Mon-Fri it came out 2d 23h. I took one story with a larger-than-average cycle time and traced it through using its history. It spanned from one week into the next, and the value made sense if I took into account that it was skipping Friday, Saturday and Sunday.

And this conveniently raises another question. I guess from seeing these two examples that “2d 9h” means 2+9/24 = about 2.4? I wasn’t sure if it was based on a 24 hour day or some concept of working hours that I couldn’t find.

Does Jira know that a 40 hr week can be mon-Thurs OR Mon - Friday depending on hr per day?