I would like to note that it would be great to have the option to add billable/non-billable to each time-entry. so not on a task basis, but on the entered time itself. sometimes an employee adds time to the system, but not all entries are billable.
I read one suggestion to use tags, but the print report option under the time tab cannot filter on tags. The report module can, but that cannot show spend time. So we basically need somekind of combination.
What a time module basically needs is reporting per task/milestone for time spend, time estimated and what time is actually billable and what not. It seems to be all in the system, but there's no option to show it in a convenient way.