Agrupamento SQL no intervalo de tempo

WITH changes AS (
  SELECT "DATE",
         CASE WHEN LAG( "DATE" ) OVER ( ORDER BY "DATE" ) + INTERVAL '5' MINUTE = "DATE" THEN 0 ELSE 1 END AS has_changed_group
  FROM   TEST
), grps AS (
  SELECT "DATE",
         SUM( has_changed_group ) OVER ( ORDER BY "DATE" ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW ) AS grp
  FROM   changes
)
SELECT MIN( "DATE" ) AS shutdown_start,
       MAX( "DATE" ) AS shutdown_end,
       MAX( "DATE" ) - MIN( "DATE" ) + INTERVAL '5' MINUTE AS shutdown_duration
FROM   grps
GROUP BY grp;

SHUTDOWN_START               SHUTDOWN_END                 SHUTDOWN_DURATION
---------------------------- ---------------------------- -----------------
07-JUL-15 12.05.00.000000000 07-JUL-15 12.15.00.000000000 0 0:15:0.0        
07-JUL-15 12.35.00.000000000 07-JUL-15 12.50.00.000000000 0 0:20:0.0        
07-JUL-15 13.05.00.000000000 07-JUL-15 13.15.00.000000000 0 0:15:0.0  

CREATE TABLE TEST ( MACHINE_ID, "DATE" ) AS
          SELECT 1, TIMESTAMP '2015-07-07 12:05:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 12:10:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 12:15:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 12:35:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 12:40:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 12:45:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 12:50:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 13:05:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 13:10:00' FROM DUAL
UNION ALL SELECT 1, TIMESTAMP '2015-07-07 13:15:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 12:35:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 12:40:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 12:45:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 13:00:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 13:05:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 13:10:00' FROM DUAL
UNION ALL SELECT 2, TIMESTAMP '2015-07-07 13:15:00' FROM DUAL;

WITH changes AS (
  SELECT MACHINE_ID,
         "DATE",
         CASE WHEN LAG( "DATE" ) OVER ( PARTITION BY MACHINE_ID ORDER BY "DATE" ) + INTERVAL '5' MINUTE = "DATE" THEN 0 ELSE 1 END AS has_changed_group
  FROM   TEST
), grps AS (
  SELECT MACHINE_ID,
         "DATE",
         SUM( has_changed_group ) OVER ( PARTITION BY MACHINE_ID ORDER BY "DATE" ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW ) AS grp
  FROM   changes
)
SELECT MACHINE_ID,
       TO_CHAR( MIN( "DATE" ), 'YYYY-MM-DD HH24:MI:SS' ) AS shutdown_start,
       TO_CHAR( MAX( "DATE" ), 'YYYY-MM-DD HH24:MI:SS' ) AS shutdown_end,
       TO_CHAR( MAX( "DATE" ) - MIN( "DATE" ) + INTERVAL '5' MINUTE ) AS shutdown_duration
FROM   grps
GROUP BY MACHINE_ID, grp
ORDER BY 1,2

| MACHINE_ID |      SHUTDOWN_START |        SHUTDOWN_END |             SHUTDOWN_DURATION |
|------------|---------------------|---------------------|-------------------------------|
|          1 | 2015-07-07 12:05:00 | 2015-07-07 12:15:00 | +000000000 00:15:00.000000000 |
|          1 | 2015-07-07 12:35:00 | 2015-07-07 12:50:00 | +000000000 00:20:00.000000000 |
|          1 | 2015-07-07 13:05:00 | 2015-07-07 13:15:00 | +000000000 00:15:00.000000000 |
|          2 | 2015-07-07 12:35:00 | 2015-07-07 12:45:00 | +000000000 00:15:00.000000000 |
|          2 | 2015-07-07 13:00:00 | 2015-07-07 13:15:00 | +000000000 00:20:00.000000000 |