Wrong values in OEM 12c physical reads/writes

Hi,

We have seen physical read write value is coming as double in OEM 12c. Difference in database and EM values.

Please suggest if OEM is showing accurate results !

SQL :-

SELECT TRUNC (END_INTERVAL_TIME) snap_date,

              TO_CHAR (ROUND (snap.BEGIN_INTERVAL_TIME, 'HH12')+1/24, 'HH12 AM')

START_time,

       TO_CHAR (ROUND (snap.END_INTERVAL_TIME, 'HH12')+1/24, 'HH12 AM') end_time,

       ROUND (snap.BEGIN_INTERVAL_TIME,   'HH12')+1/24 BEGIN_INTERVAL_TIME,

       ROUND (snap.END_INTERVAL_TIME, 'HH12')+1/24 END_INTERVAL_TIME,

       sysstat.dbid,

       snap.instance_number,

       snap.snap_id,

       stat.stat_name,

       sysstat.VALUE VALUE,

       SYSDATE

  FROM dba_hist_sysstat sysstat