Oracle 10 RAC VIP returns non-VIP address for client

I am not a DB or even Oracle expert, but I wanted to understand when and why Oracle returns a different non-VIP address to the client, assuming this is correct behaviour?

listener.ora

LISTENER_DB-A =
(DESCRIPTION_LIST =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = DB-A-VIP)(PORT = 1521)(IP = FIRST))
       # this is the VIP 10.0.0.15
    )
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 10.0.0.10)(PORT = 1521)(IP = FIRST))
    )
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
    )
  )
)

Here, after connecting to the IP address 10.0.0.15, the Oracle server returns the 10.0.0.10 address to the client. This is my network sniff of the said behaviour:

Client to Oracle

(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=10.0.0.15)(PORT=1521)))
(CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))(SERVER=DEDICATED)
(SERVICE_NAME=kdtest_db)(FAILOVER_MODE=(TYPE=SELECT)(METHOD=BASIC)(RETRIES=5)(DELAY=5))))

Oracle to Client

(DESCRIPTION=(CONNECT_DATA=(SERVICE_NAME=DB-A))(ADDRESS=(PROTOCOL=TCP)(HOST=10.0.0.10)(PORT=1521)))

I know that this behaviour is not mandatory, as I've seen Oracle server respond without said redirection. What is the reason the server is acting this way? Thanks in advance!