Update Date based on the condition

DECLARE @TEST_DATA TABLE (DT_ID INT IDENTITY(1,1) NOT NULL PRIMARY KEY CLUSTERED, JobNumber VARCHAR(10) NOT NULL, JobStatus CHAR(1) NOT NULL, ExpectedDate VARCHAR(10) NOT NULL, LastShippedDate VARCHAR(10) NULL);

 INSERT INTO @TEST_DATA (JobStatus, JobNumber,ExpectedDate,LastShippedDate) 
 VALUES
  ('S', 'J012345','2014-06-26','2014-07-03') ,('O', 'J012346','2014-07-03',NULL        ) ,('O', 'J012347','2014-07-03',NULL        ) ,('O', 'J012348','2014-07-10',NULL        ) ,('O', 'J012349','2014-07-10',NULL        )
 ,('O', 'J012350','2014-07-10',NULL        ) ,('O', 'J012351','2014-07-10',NULL        ) ,('O', 'J012352','2014-07-17',NULL        ) ,('O', 'J012353','2014-07-17',NULL        ) ,('O', 'J012354','2014-07-17',NULL        )
 ,('O', 'J012355','2014-07-17',NULL        ) ,('O', 'J012356','2014-07-17',NULL        ) ,('O', 'J012357','2014-07-24',NULL        ) ,('O', 'J012358','2014-07-24',NULL        ) ,('O', 'J012359','2014-07-24',NULL        ) 
 ,('O', 'J012360','2014-07-24',NULL        ) ,('O', 'J012361','2014-07-24',NULL        ) ,('O', 'J012362','2014-07-31',NULL        ) ,('O', 'J012362','2014-07-28',NULL        );                                       

 SELECT J.DT_ID, J.JobStatus, J.ExpectedDate, J.LastShippedDate,  
 CASE 
     WHEN j.JobStatus <>'S' AND Cast(J.ExpectedDate as Date) <= CONVERT(DATE,GETDATE()) THEN Dateadd(day,4,cast (DATEADD(week, DATEDIFF(week,0,GETDATE()),-1) AS DATE))   
     WHEN j.JobStatus ='S' then Cast(j.LastShippedDate AS DATE) 
         ELSE Cast(J.ExpectedDate AS Date) 
 END AS TestNewShipDate
 FROM @TEST_DATA J

Slight change to the case criteria so it compared to todays date, rather than the start of next week.