enq: TX - contention between insert statement and DBMS_STATS

Oracle 10.2.0.4

ADDM is reporting high "enq: TX - contention" waits for an insert statement into a table that is range partitioned by date (one day per partition).  These inserts occur all day long at various rates depending on the incoming data.  Each hour, we execute dbms_stats.gather_table_stats on "today's" partitions (to which the inserts are going) using granularity=>"PARTITION",no_invalidate=>TRUE,esitmate_percent=>10.  We have to do this because we get tens of thousands of inserts per hour.  This stats job is monitored, and is not permitted to run for more than 10 minutes.  If it is running for more than 10 minutes, it is killed.  For