Hey,
Specific to Cases the Case# is populated by the RecordID. The RecordID will always go sequential, (1, 2, 3,) we cannot adjust that.
Alternativally we can add a field to the Cases Table (e.g. RefNumber) in which we can control the # order.
You can look at how it works on the stock Activities Tab within the NewActivity screen. Take a look at the Save action and Action #54 you can see how the Related Act. # gets updated with the RecordID - using the Character Function you can alter how it's displayed and then using an Insert Records into Table you can push it into the RefNumber field you made in the Cases table.
Now add the RefNumber to the Grid to the ActivityList screen to view.
- Mortaza