Is the return result of command zmmsgtrace accurate?

[POla]

I am using smtp client to send email alert through zimbra.
Some of the recipient claimed that they didn't receive the alert email.
I run the command zmmsgtrace -i/-s/-r/-t to trace the email status.
1st case:

Message ID '021a01c9328a$6a73f630$2e04f403@schlaptop'
xyz@abc.com -->
                zabarang67@yahoo.com
  Recipient zabarang67@yahoo.com
  2008-10-20 16:02:50 - unknown (60.75.33.115) --> mail
  2008-10-20 16:02:50 - mail --> 127.0.0.1 (127.0.0.1]:10024) status sent

but I check the log and see:

Oct 20 16:02:52 mail postfix/smtp[24305]: E25B937FB4F: to=<zabarang67@yahoo.com>, relay=b.mx.mail.yahoo.com[66.196.97.250]:25, delay=2, delays=0.03/0/1.2/0.7, dsn=5.0.0, status=bounced (host b.mx.mail.yahoo.com[66.196.97.250] said: 554 delivery error: dd This user doesn't have a yahoo.com account (zabarang67@yahoo.com) [0] - mta209.mail.re3.yahoo.com (in reply to end of DATA command))

* The log record and result returned by command is not the same.

2nd case:

Message ID '4038418.181224488985260.JavaMail.root@mail.sch.com'
xyz@abc.com -->
                hardtoky@yahoo.com
  Recipient hardtoky@yahoo.com
  2008-10-20 15:49:45 - localhost (127.0.0.1) --> mail
  2008-10-20 15:49:46 - mail --> 127.0.0.1 (127.0.0.1]:10024) status sent
  2008-10-20 15:49:48 - mail --> 127.0.0.1 (127.0.0.1]:10024) status bounced
    (host e.mx.mail.yahoo.com[216.39.53.1] said: 554 delivery error: dd This user doesn't have a yahoo.com account (hard2say5nk@yahoo.com) [0] - mta136.mail.re4.yahoo.com (in reply to end of DATA command))

* The result returned by command directly show that it is bounced.

3rd case:

Message ID '27270208.40351223535567718.JavaMail.SYSTEM@mail.sch.com'
xyz@abc.com -->
                ky@living.com
  Recipient ky@living.com
  2008-10-09 14:51:46 - localhost (127.0.0.1) --> mail
  2008-10-09 14:51:49 - mail --> living.com (202.55.15.37]:25) status sent
      by amavisd on  () HITS:  in  ms

* From above, the record show mail --> living.com (202.55.15.37]:25) but for the 1st and 2nd case, it is mail --> 127.0.0.1 (127.0.0.1]:10024). Why it is different? Why the 1st and 2nd case record not like mail --> c.mx.mail.yahoo.com (216.39.53.2) ?

Can I determine whether an email has delivered to its recipient through the status returned by command zmmsgtrace? Is it accurate?