RAC: Log switch frequency script

The following script reports how much time passed between log switches in a time period.
Although it's written to provide information per instance in RACs, it will also work in Single Instances.

SELECT C.INSTANCE,
         C.THREAD#,
         B.SEQUENCE# "START SEQUENCE",
         TO_CHAR (B.FIRST_TIME, 'DD-MM-YYYY HH24:MI:SS') "START TIME",
         A.SEQUENCE# "END SEQUENCE",
         TO_CHAR (A.FIRST_TIME, 'DD-MM-YYYY HH24:MI:SS') "END TIME",
         TO_CHAR (
            TRUNC (SYSDATE)
            + NUMTODSINTERVAL ( (A.FIRST_TIME - B.FIRST_TIME) * 86400,
                               'SECOND'),
            'HH24:MI:SS')
            DURATION
    FROM V$LOG_HISTORY A, V$LOG_HISTORY B, V$THREAD C
   WHERE     A.SEQUENCE# = B.SEQUENCE# + 1
         AND A.THREAD# = C.THREAD#
         AND B.THREAD# = C.THREAD#
         AND A.FIRST_TIME BETWEEN TO_DATE ('23-07-2012 00:00:00',
                                           'DD-MM-YYYY HH24:MI:SS')
                              AND TO_DATE ('24-07-2012 00:00:00',
                                           'DD-MM-YYYY HH24:MI:SS')
ORDER BY 4;

Let's try it for a day, e.g. 23/07/12:   

INSTANCE	THREAD#	START SEQUENCE	START TIME	END SEQUENCE	END TIME	DURATION
OTE1	1	436571	22-07-12 23:59:44	436572	23-07-12 00:08:12	00:08:27
OTE2	2	402951	22-07-12 23:59:46	402952	23-07-12 00:15:31	00:15:45
OTE1	1	436572	23-07-12 00:08:12	436573	23-07-12 00:11:48	00:03:36
...	...	...	...	...	...	...
OTE2	2	403315	23-07-12 23:57:51	403316	23-07-12 23:59:42	00:01:51
OTE1	1	436873	23-07-12 23:58:15	436874	23-07-12 23:59:10	00:00:54
OTE1	1	436874	23-07-12 23:59:10	436875	23-07-12 23:59:40	00:00:29