Try this.
=IF(CELL("format",C1)="P0",A1*C1,TEXT(C1/A1,"0%"))
Sample is uploaded at
https://skydrive.live.com/view.aspx?cid=FC7700310D509404&resid=FC7700310D509404%21136
Prima facie, I think you need to update data source of the pivot table. Your pivot is not picking up on Aug/ July data. Update data source by clicking on Option > Change Data Source.
However, you can upload it in Sky drive/ Rapid-share or similar sites, for better understanding..
Whenever your total of hh:mm goes above 24 hours, it will not show 25:00 but will show 1:00, for example.
Also, even though it shows 1:00, value under hood is still equal to 25:00, hence if you want to do something with this value it will still behave as 25:00.
it has nothing to with H9, but...
Does this help??
https://skydrive.live.com/view.aspx?cid=FC7700310D509404&resid=FC7700310D509404!135
I know it's a lazy way of doing it, but it does the job.