Time issue

Ok,
I'm having a problem with time.

Lets says:

Mon Tue Wed Thurs Fri Total hrs
8 am 3 pm no work NW NW 5 pm- 3am -number

On my total hours I get a minus total number. the problem is in the calculation on Fri. When it goes on to the next day my hours doesn't come out right.

Here is my file.

The problem occurs because yuor timespan has gone past midnight.

Try making amendments like

(IF(L3>K3,(L3-K3)*24,(L3+1-K3)*24))

to your formula