How can I create totals for standard calculated attributes?

Hello Team I have some standard calculated attributes like below: 

However I need to calculate total of the hours worked rows to summarise all the hours worked by the engineers on each ticket. So for example one ticket may have 4 active engineers with 4 sets of hours and i'd need the total to appear as a separate column at the end. 

They are standard calculated attributes as It was hard to add them in the correct order as metrics and the ticket fields are also numeric. 

Attribute is calculated like below: