Calculating Rostered Hours

I have what is essentially a simple problem, I want to calculate employee rostered hours or days off from an exported crystal reports. The problem isn't how to calculate the hours but to calculate accurately when formatting changes occur in the exported report. This is an example for the exported sheet data.

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So to calculate data intially using the formula

=IF(F4>0,(G4-F4)+(F7-E6)+$L$6,E5)

works fine.

But since as you can see the formatting changes in first calculate there are 4 rows for the second day there are 3 rows and if its a day off one row and calculation of next day begins on following row.

Is there any way to overcome this, I need to learn how to create a macro of this for example the above is from one employee 6 month to december and there are another 70 employs to go.

My goal would be to end up with output like.

\1

ShiftTrack - Shift and Roster Management	Page -1 of 1				Date	Hours	
Bereavement	13:15	17:45	ShiftTrack - Shift and Roster Management	Page -1 of 1			
17:45	18:15	ShiftTrack - Shift and Roster Management	Page -1 of 1				
18:15	20:00	ShiftTrack - Shift and Roster Management	Page -1 of 1				0:10
20:00	21:00	ShiftTrack - Shift and Roster Management	Page -1 of 1		2/07/2009	7:25	
Bereavement	13:15	17:45	ShiftTrack - Shift and Roster Management	Page -1 of 1	3/07/2009	7:25	
17:45	18:15	ShiftTrack - Shift and Roster Management	Page -1 of 1		4/07/2009	7:25	
18:15	21:00	ShiftTrack - Shift and Roster Management	Page -1 of 1		5/07/2009	5:00	
Claims A	12:15	16:00	ShiftTrack - Shift and Roster Management	Page -1 of 1	6/07/2009	5:00	
16:00	16:30	ShiftTrack - Shift and Roster Management	Page -1 of 1		7/07/2009	7:25	
16:30	20:00	ShiftTrack - Shift and Roster Management	Page -1 of 1		8/07/2009	Day Off	
DAY OFF			ShiftTrack - Shift and Roster Management	Page -1 of 1	9/07/2009	Day Off	
Claims M	15:15	19:45	ShiftTrack - Shift and Roster Management	Page -1 of 1			
19:45	20:15	ShiftTrack - Shift and Roster Management	Page -1 of 1				
20:15	23:00	ShiftTrack - Shift and Roster Management	Page -1 of 1

The links above contain images showing the examples,, it may be clearer from them the exact layout.