subtracting time adds 1 month

[sick stigma]

In this formula, I am subtracting a 2 column date and time from another 2 column date and time, excluding Saturdays and Sundays. Somehow it seems to be adding a month to the calculation. A cell that should equal 00,00,4:56 will equal 01,00,4:56.
Suggestions?

Thanks,
Sick

[Norie]

Can you attach a workbook with some example data?

[sick stigma]

here is the workbook as it currently exists.
Sick

[Norie]

I think this might be a formatting issue.

If I change the formatting of J16 (01,01,08:37) to dd/mm/yyyy hh:mm the result displays as 01/01/1900 08:37.

If I do the same for J31 it displays (01,00,09:12) as 00/01/1900 09:12

[sick stigma]

But in either case there was no month or year elapsed. In dd,mm,yyyy hh:mm they should be 01,00,00 8:37 and 00,00,00 9:12.
Where is that D**N month coming from. I just can't find my mistake.
Sick

[Norie]

A month hasn't been added.

The result you have is a date and the month of that date is January, so your format of mm displays 01.

[sick stigma]

Got it! Thanks!