왜 22일에서 44로 되나요?

SELECT empno, trainymd, SUM(duttm) OVER(PARTITION BY empno, gb ORDER BY trainymd) AS amt
FROM 
(
  SELECT T.*, SUM(DECODE(hcnt, 12, 1, 0)) OVER(PARTITION BY empno ORDER BY trainymd) gb
  FROM T
)

WITH T AS (
SELECT '216990'   EMPNO
     , '20171211' TRAINYMD
     , 0          HCNT
     , 22         DUTTM FROM DUAL UNION ALL
SELECT '216990' , '20171212' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171213' , 0   , 11 FROM DUAL UNION ALL
SELECT '216990' , '20171214' , 12  , 21 FROM DUAL UNION ALL
SELECT '216990' , '20171215' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171216' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171217' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171218' , 0   , 11 FROM DUAL UNION ALL
SELECT '216990' , '20171219' , 12  , 11 FROM DUAL UNION ALL
SELECT '216990' , '20171220' , 12  , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171221' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171222' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171223' , 0   , 22 FROM DUAL UNION ALL
SELECT '216990' , '20171224' , 0   , 22 FROM DUAL 
)
SELECT trainymd
	  ,SUM(duttm) OVER(PARTITION BY gb ORDER BY trainymd) 
FROM(
SELECT trainymd
	  ,duttm 
	  ,SUM(hcnt) over(PARTITION BY empno ORDER BY trainymd) gb  
FROM t )