I have noticed that a "Rejection comment" field is available in the Hour schema, but at this time there is no way to add this comment through Workfront interface; this has been confirmed to me by a Workfront support representative. We can add the field in a view, but users have no way to enter information in it!
In my company the ability to add a rejection comment is important for the timesheet/hour approval process, and now users are forced to add information to the hour description, mixing the rejection comment with the hour description entered by the hour owner, which is far from the ideal situation.
It would be enough to add a textarea in the hour edit window, since it seems that the Workfront database already has the field available, so this should not be a very time-consuming feature to add.
Thanks for your attention!
Andrea Benfenati