Oracle11g password expiry issue
According to the Oracle documentation here (see heading Setting the PASSWORD_LIFE_TIME Profile Parameter to a Low Value) the account status is changed from OPEN to EXPIRED(GRACE) if the user is currently logged in when you change PASSWORD_LIFE_TIME to a low value. I guess you were logged in as system when you changed the PASSWORD_LIFE_TIME. Try logging in as CUSUSER and then changing it.

The following method will set a user's account status to EXPIRED(GRACE):

create profile EXPTESTPROF limit
failed_login_attempts             1
password_life_time                1/24/60/60
password_reuse_time               unlimited
password_reuse_max                1
password_verify_function          null
password_lock_time                1
password_grace_time               1;

create user EXPTEST identified by EXPTEST;

alter user EXPTEST profile EXPTESTPROF;

grant "CONNECT" to EXPTEST;


Then login as EXPTEST. You'll get the message that the password will expire within 1 day. If you check the ACCOUNT_STATUS now it should say EXPIRED(GRACE):

select ACCOUNT_STATUS
  from DBA_USERS
 where USERNAME = 'EXPTEST'