TNS LOAD_BALANCE = ON doesn't seem to work.

Hi, we have 2 servers with 3 identical databases on each box, and using the same kind of tns entry for load balancing.

For 2 databases load balancing is working as expected but only one, it's not, this is our tns entry:

cms=

(DESCRIPTION=

   (LOAD_BALANCE=on)                                   

   (ADDRESS_LIST=

     (ADDRESS=(PROTOCOL=tcp)(HOST=ch-rptdb-p04.compsych-ad.int)(PORT=1521))   

     (ADDRESS=(PROTOCOL=tcp)(HOST=ch-rptdb-p03.compsych-ad.int)(PORT=1521)))

   (CONNECT_DATA=(SERVICE_NAME=cms))) 

  

Please advise/guide, how to troubleshoot & resolve this when we have the same kind of load on all the 3 databases, for 2 it's working fine but for one of the database, the load balancer doesn't seem to be working, all the jobs are going to one database only, whereas it should load balance.