What happens when I change a task from non-billable to billable?

When time is logged for a task that is marked as non-billable, Billable Time spent is 0 hours.

• If you decide to mark this task as billable and there are several time logs for this task, you have an option to convert these timelogs as billable. 
• With this change, billable time spent is incremented by the total value of the updated time logs.

To know more about Timelogs, click here.