Reflecting Last Data Values Using Calculated Item

I have a pivot where one of my coloumn""Interval Type" has "Break Start", "Break End", "Login", "Logout" and "Total Break" as the field items. What i want to do is to get a field which will subtract my Break End to my Break Start so that i Get Total Break. In row label i have Advisor name.

When i am using Calcualted Item option its doing the calcultion basis the first values available in the databse, however i have users taking multiple breaks and i want to get the last item calcualted available in the list.

I know its kinda complex, but can we do something about it please...

Can you provide data?