You can get the sum column's time data by grouping statuses.
This Status Groups function is available for the following reports:
Time in Status
Time in Status per Date
To get the sum, go to the Status Groups. Here, you can:
Add a name to your custom column and select statuses you want to group.
As a result, you'll get one column with summed data from your previously selected columns.
A status group function lets you calculate Cycle and Lead Time.
Read more about User Groups.