Work Request Status in Oracle eAM

Oracle eAM support following statuses of  Work requests.

1-Open

2-Additional Information

3-Awaiting Work Order

4-On Work Order

5-Rejected

6-Complete.

System will not let user Change the Status (Where ever possible /Supported)  of Work Request if existing status of WR(Work request) is not in above 6.

Many a time I found that technical team create a New Status say "cancelled" with status code ( > 6) and then  update work request with it , but latter on if someone try to make any Change in the WR, system will raise error. 

Or If user try to un-check the Maintenance flag from the Asset and if that Asset has any WR whose status in not in 1 to 6 , system will not let user to un-check the maintenance flag..