Even after years in the business you still get these moments: "Ok, why is this not working? wtf?". It happened to me recently while moving applications between hosts. I did not notice that one of the settings for the application was using php_admin_value.
The difference is described in details here: php configuration settings
My problem was that i tried to override that same setting in the .htaccess file in the application's folder and i could not see why it was not working. It took me a while before i started googling for it as everything seemed fine : )
Bottom line is if you set settings in httpd.conf or php.ini using php_admin_value they wont be overridden by any values set in htaccess files :)
Oh well ... what can you do we all make mistakes :)