|Sorry about the posting - I'm new to this - hope this is more readable|
Times in Excel appear difficult, but if you ensure that all data entry follows a time format that Excel recognizes, you will be able to add and subtract times without any need to use INT or TIME
Enter start and finish times as hh:mm, for example 07:30
Format all the cells used for time entry and time calculations with "hh:mm"
The duration of work is just Finish-Start
Start time in A2 07:30
Finish time in B2 11:10
Duration in C2 has the formula =B2-A2
and if formatted "hh:mm" will show 3:40, ie 3 hours and 40 minutes
If staff may work past midnight use the following formula
This adds 1 to the finish time when the finish time is 'earlier' than the start time, because the finish time is in the next day.
Excel's date/time serial number holds dates in the integer part of the serial number and times in the decimal part of the number.
For example 09 September 2009 is 40066
12 noon on 09 September 2009 will be 40066.5 i.e. half way through the day.
Only do your decimal conversion for input into the payroll system as a final step - don't mix decimal calculations and Excel's time serial numbers
If the final hours:minutes to be converted are in cell F2
put hours in G2 with this formula
and minutes as a decimal part of an hour in H2 with this formula =MINUTE(F2)/60
I know this doesn't answer your specific questions, but it will likely be easier to start from scratch just using Excel's time system,
(and program maintenance will be easier in the future).
By the way Excel's serial number does not handle negative time values. If you needed to have time debited, keep the value positive but label the cell or group of cells as debit or time owing or whatever and just subtract the positive number rather than trying to add a negative value.
You may want to consider adding data validation to input cells so that time entries are never greater than 1 (1=12 midnight).