The reports currently show the total amount of time units billed for each ticket. However, if monthly reports are sent to the customer in the form of invoices, it would be useful to have another column called TU billed on date/time (the name of the column can be changed), where the time and date of the billed units would be added to the reports. This would show how many units were billed on which day and by which agent.
As an example:
Agent A bills 20 time units, Agent B (who also owns the ticket) bills another 12 time units. The exported file shows the information about the owner and the total (32) amount of billed units. However, it is not apparent whether the billed units were all billed on the same day, or whether they were separated by 1, 12, or 30 days. It can be seen in the history of each single ticket, but not in the reporting .xls file.