Hi Keith,
No it should say "mod_gzip". If it doesn't then it is probably not installed... These two options are the only things I have found to fix this. Could your server be doing other buffering or processing, such as via a PHP extension that modifies output?
Via Google I've seen that enabling "output_handler" in /etc/php.ini can inadvertently enable the "output_buffering" we do not want. That should be disabled by default, though.
Ironically, I'm having the same problem on a server I recently set up. I am searching for a solution and will let you know if I find one.
Regards