R12 :Why 2 records in ad_applied_patches

hello,

The above are the patches applied since August, here most patches has 2 records and few has only one record in ad_applied_patches and why is that.

SQL> set line 100;
SQL> col patch_name form a10;
ALTER SESSION SET nls_date_format='MM/DD/YYYY HH24:MI:SS';
SQL>
Session altered.

SQL> select applied_patch_id,patch_name,creation_date from apps.ad_applied_patches
where to_date(creation_date,'MM/DD/YYYY HH24:MI:SS') BETWEEN
2    3  TO_date ('08/11/2014 23:59:59', 'MM/DD/YYYY HH24:MI:SS')
4  AND TO_date ('09/05/2014 00:00:00', 'MM/DD/YYYY HH24:MI:SS')
order by creation_date desc;  5