Oracle Database Discussions

I have the following configuration:

CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 35 DAYS;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK;
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO 'D:\SOMEPLACE\SOMENAME.ORA'; # default

list backup; returns:

List of Backup Sets
===================

BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
1674 Full 1G DISK 01:34:00 05-JUL-07
BP Key: 1674 Status: AVAILABLE Tag: TAG20070705T181021
Piece Name: E:\BACKUP\SID\FULL_1_20070705_KJIM39KD_1_1
Controlfile Included: Ckp SCN: 637088837 Ckp time: 05-JUL-07
List of Datafiles in backup set 1674
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
1 Full 637088838 05-JUL-07 E:\ORACLE\ORADATA\SID\SYSTEM01.DBF
33 Full 637088838 05-JUL-07 E:\ORACLE\ORADATA\SID\AUDIT09.DBF
37 Full 637088838 05-JUL-07 E:\ORACLE\ORADATA\SID\INDX09.DBF
38 Full 637088838 05-JUL-07 E:\ORACLE\ORADATA\SID\INDX10.DBF

-----
lots of backups omitted
-----

BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
2547 845M DISK 00:14:39 17-SEP-07
BP Key: 2547 Status: AVAILABLE Tag: TAG20070917T180007
Piece Name: E:\BACKUP\SID\AL_DSID_T633554081_S2565_P1

List of Archived Logs in backup set 2547
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 16002 665550300 17-SEP-07 665550725 17-SEP-07
1 16003 665550725 17-SEP-07 665551361 17-SEP-07
1 16004 665551361 17-SEP-07 665557505 17-SEP-07
1 16005 665557505 17-SEP-07 665561201 17-SEP-07
1 16006 665561201 17-SEP-07 665561546 17-SEP-07
1 16007 665561546 17-SEP-07 665561930 17-SEP-07
1 16008 665561930 17-SEP-07 665564710 17-SEP-07
1 16009 665564710 17-SEP-07 665571852 17-SEP-07
1 16010 665571852 17-SEP-07 665600810 17-SEP-07
1 16011 665600810 17-SEP-07 665610536 17-SEP-07
1 16012 665610536 17-SEP-07 665616271 17-SEP-07
1 16013 665616271 17-SEP-07 665627484 17-SEP-07
1 16014 665627484 17-SEP-07 665633521 17-SEP-07
1 16015 665633521 17-SEP-07 665643772 17-SEP-07
1 16016 665643772 17-SEP-07 665652071 17-SEP-07
1 16017 665652071 17-SEP-07 665660217 17-SEP-07
1 16018 665660217 17-SEP-07 665672601 17-SEP-07

Recovery Manager complete.

have done crosscheck backup;

report obsolete; tells me that no backup is obsolete.

Any ideas of why non of the backupset are marked as obsolete.