hh:mm:ss and mm:ss computations

[exceluab]

Can someone assist me with computations on the following worksheet? http://tinypic.com/r/2qlv1c4/7 I need to do computations with times that may vary from hh:mm:ss and mm:ss. I have attached a photo of the spreadsheet. And I would like to do computations like this. I need to have all the computations occur for every employee number listed (1-64) and it needs to use Agent Time for the number that the deductions occur from. Can someone help?

 

[machopicho]

Copy formulas from here:
http://www.megaupload.com/?d=EYO9EKOS

 

[exceluab]

The problem I am having does not lie with simple mathematical calculations using minutes.

The problem I am having is---getting hh:mm:ss and mm:ss into a computational form. This is the only format in which the phone system exports time values. Please see my screen shot of the spreadsheet.