Mark,
I managed to fix the stats issue by issuing /opt/zimbra/libexec/zmsyslogsetup on the logger server. Before the status was logging for just the proxy server. Now it's neatly populating the mailbox servers. Thanks for your help.
However, one thing I found was that the binary for zmsyslogsetup on logger host with 6.0.7 was safe in /opt/zimbra/libexec instead of /opt/zimbra/bin. All these while I was looking for it to update the logger host to reset it and get the stats populating. No regrets, got working into lot of areas
Before the /var/log/zimbrastats.log had no entries for mailbox servers even though the daily mail reports were properly working. And I could find /etc/syslog.conf a bit scrambled up which could have also caused it. Syslogd was set to restart everyday around 15.00. Anyway thanks for your time Mark
PS. Since the latest version 6.0.7, zmsyslogsetup resides in /opt/zimbra/libexec!