GROUP BY CLAUSE HELP

HELLO FOLKS

I AM RUNNING THIS BELOW QUERY AND I DIDN'T GET WHY IS REPEATING ROWS. CAN YOU PLEASE ADVISE WHAT'S WRONG WITH THIS QUERY. I NEED TO HAVE SINGLE LINE RESULT FOR BELOW QUERY.

SELECT 
T4.[ItemCode], 
T4.[Dscription], 
T2.[FirmName], 
SUM(T3.[OnHand]) as 'On Hand', 
Case when T4.[ShipDate] < getdate() then Sum(T4.[Quantity]) end as 'BO',
case when T4.[ShipDate] > getdate() then Sum(T4.[Quantity]) end as 'FC' 

FROM 

OITM T0 

INNER JOIN OITB T1 ON T0.[ItmsGrpCod] = T1.[ItmsGrpCod] 
INNER JOIN OMRC T2 ON T0.[FirmCode] = T2.[FirmCode] 
INNER JOIN OITW T3 ON T0.[ItemCode] = T3.[ItemCode] 
INNER JOIN RDR1 T4 ON T0.[ItemCode] = T4.[ItemCode] 

WHERE 

T3.[WhsCode] = '100' and
T4.[LineStatus] = 'O'


GROUP BY 

T4.[ItemCode], 
T4.[Dscription],
T2.[FirmName],
T4.[ShipDate]

bo-fc.jpg