As an alternative, you can use the Resource Usage report. It will give you the totals as well.
In the code above, you can replace pjTimescaleDays with one of the other unit enumerations: https://msdn.microsoft.com/en-us/library/office/bb223241(v=office.12).aspx. And note that both the code and the report can be customized for a date range and a period.
