OLS sa_session.set_access_profile taking way too long

We are using Oracle 10.2.0.4.  We have implementing a connection pool, and as each application user is assigned a connection, the application calls a very short stored procedure which executes "sa_session.set_access_profile (policy_name, user_name)."  This ONE LINE is taking 4.5 seconds to execute on our production database.  This does not seem reasonable at all.  However, we have recently had to change a number of OLS groups into OLS compartments by creating the compartments of the same names, giving each user of the group the ability to see the compartment, relabeling all the data, dropping the group from the users, and finally dropping the groups themselves.  Could the LBACSYS tables be badly fragmented?  If so, how do we fix them?  We do run dbms_stats.gather_dictionary_stats on a daily basis, so the stats on the LBACSYS