Tony,
I have created a custom field on an Issue Custom Form called "Number of Days - Life" to calculate the number of WorkDays between the Entry Date of the Issue and the Completion Date of the Issue.
The calculation is as follows:
WEEKDAYDIFF(CLEARTIME(Entry Date),CLEARTIME(Actual Completion Date))
I included the "clear time" parameter, because in the past, I have had problems with the date not calculating as the user had expected, but only because Workfront was also considering the time component of the Date. Using CLEARTIME, levels the playing field so-to-speak and eliminates confusion since we really drive our work by Date, excluding time.
When you convert an Issue to a Project and keep them linked, when you close the Project, the Issue will automatically close. When it closes, the Issue will be set to the Actual Completion Date for the Project it is linked and the custom data on your form will be refreshed (I've only see it automatically refresh when a status change is made to the Issue, any other changes that you do, you will have to refresh the custom data yourself.
Side note, in Project Preferences we have the following settings:
When converting an issue to a PROJECT... "Keep the original issue and tie its resolution to the project"
When a task or issue is completed, set the Actual Completion Date to..."Now".
**Caution, when an Issue is linked to a Task/Project there are instances where the Issue Status "Closed" is not reflective of the Task/Project Status. Workfront treats the relationship from the Task/Project in terms of "completion" as a one-and-done type of communication back to the Issue. Which in my opinion, is not ideal; we have to have special exception reports to monitor this so another group can fix the statuses when they are out of sync. Basically, this happens when a resource changes the status of a Task/Project to Complete, prematurely, only to re-open the Task/Project for continued activity. However, once the Task/Project sends the "closed" notification to the Issue it resolves, the Issue status gets set to closed and the Actual Completion Date gets populated. The Issue doesn't pay attention to any changes to the Task/Project, after the fact.
To correct this problem I do the following: Go to the Issue Overview tab, Edit Overview, Copy the value displayed in the Task/Project field located next to the Resolved By field to your clipboard, change the Resolved By field to "Select Resolving Object", and click the Save Button to temporarily remove the link. We also change the Status on the Issue back to the prior status it had before getting closed.
Then while you are still on the Issue, Edit Overview, select the appropriate value in the Resolved By field, paste the Task/Project Name you saved to your clipboard back into the field, and click the Save Button. This will reestablish the link and reset the Status to match the Task/Project again.
I have had this as an open issue/enhancement with Workfront since 2013. They said the feature is working as designed so I had submitted it as an enhancement some years ago. So far it hasn't been fixed. Sorry for that long-winded "caution", I wasn't sure if you were aware of it or not.
Good luck, I hope this helps.
