Hope this helps:

All calculations are on Row 5 for that day, Monday
The next days hours will follow are on the next Rows as needed.

"A" Column Time Start in Military Time Format (18:00)
"B" Column Time Stop in Military Time Format (08:00)

What's need to calculate from Columns "A" & "B".

"C" Column Total Regular Hours worked in NUMERICAL Value (8.0)
"D" Column Total Overtime Hours (if any over Regular Hours) in NUMERICAL Value (2.0)

Have I confused everyone yet?!