"Before down for maintenance" notice is an error instead of warning?

Running 1.3.9c. When I enable "NOTICE PUBLIC Before going Down for Maintenance: ON/OFF" in my admin, the message "NOTICE: This website is scheduled to be down for maintenance on: 15/05/2003 2-3 PM" appears, as expected, in my store's header message ... but the message is formatted as an error (i.e. red background) instead of a warning (yellow background).

I'm not sure if this was intended, but I made the following change (in red) to /includes/init_includes/init_header.php to get the message to display as a warning:

// give the visitors a message that the website will be down at ... time
if ( (WARN_BEFORE_DOWN_FOR_MAINTENANCE == 'true') && (DOWN_FOR_MAINTENANCE == 'false') ) {
  $messageStack->add('header', TEXT_BEFORE_DOWN_FOR_MAINTENANCE . PERIOD_BEFORE_DOWN_FOR_MAINTENANCE, 'warning');
}

The Notice is in RED ... if you want it in YELLOW change it to a:
caution