Sum using ObjectID

[Athira_K]

Hello,
I have a listbox built using expression(=if(F=1,Interval(Stop-Start,'hh:mm:ss')) from chart.
I want to calculate the sum of that listbox.

Is there anyway we can use Object ID of this listbox for calculating the sum?

Note:
Sum(expression) is not working as expected because the F boolean has soo many values for 1 in other table.
Thank you