[syslog-ng]logrotate

Hi all, I'm just wondering why I have to restart syslog-ng after logrotate ? If I can do echo -n > /var/log/messages and everything works fine then why logrotate can not do it ? I believe that if I restart syslog-ng there is potential risk of loosing one line of logs, when syslog-ng is down. I assume it is better not to restart it then. Am I thinking correct or not ? Thank you. M.