Be more specific about what you are doing. As (minimally) stated, the
answer you claim to get cannot occur in Excel.
Excel stores times as fractions of days, regardless of the format
(military, AM/PM, etc. Excel does give 0.151388888888889 (3:38:00) as
the answer for =0.956944444444444-0.805555555555555 (22:58:00-19:20:00).
You claim to be getting 0.848611111111111, which cannot occur with the
problem as you have stated it, but is is the answer to
=1.805555555555555-0.956944444444444 (19:20:00-22:58:00), provided that
the these times include dates, and the date for 19:20:00 is the next day
after the date for 22:58:00
Jerry