DESC Index Is Not Being Used

I have Oracle database 11.2 running. I have been under the impression that Oracle would use DESC index for better performance if I select MAX () ..., but this is not true. Example:

CREATE INDEX IX1_TASK_PROCESS_BATCH ON TASK_PROCESS_BATCH (seq);
CREATE INDEX IX2_TASK_PROCESS_BATCH ON TASK_PROCESS_BATCH (seq DESC);

There are more than 840K rows in this table, and SEQ is unique and not null.

EXEC Dbms_Stats.gather_table_stats ('','TASK_PROCESS_BATCH');

EXPLAIN PLAN FOR
SELECT MAX (SEQ) FROM TASK_PROCESS_BATCH;

SELECT * FROM TABLE(dbms_xplan.display());

PLAN_TABLE_OUTPUT
Plan hash value: 2378415181