This replacement of exclude_node_title_form_alter replaces the exclude checkbox with a message if it's already excluded in type.

I would like you to apply this code to the module for the future release.
It will replace the Exclude Checkbox if the editing node's content type is now already excluded by the main settings.

function exclude_node_title_form_alter(&$form, &$form_state, $form_id) {
  if (isset($form['type']) && isset($form['#node']) && $form['type']['#value'] .'_node_form' == $form_id) {
    if (!user_access('exclude any node title')) {
      global $user;
      if (!user_access('exclude own node title') ||
              ( user_access('exclude own node title') && strcmp($form['#node']->name, $user->name) ) ) {
        return FALSE;
      }
    }
    $weight = $form['title']['#weight']+1;
    static $exclude_node_title_content_type;
    if (!isset($exclude_node_title_content_type)) {
      $exclude_node_title_content_type = variable_get('exclude_node_title_content_type_values', array());
    }
    if ($exclude_node_title_content_type[$form['#node']->type]) {
      $form['title']['#description'] = t('This title is excluded from display');
    } else {
      $form['exclude_node_title'] = array(
        '#type' => 'checkbox',
        '#title' => t('Exclude title from display'),
        '#required' => FALSE,
        '#default_value' => (!empty($form['nid']['#value']) ? in_array($form['nid']['#value'], variable_get('exclude_node_title_nid_list', array())) : FALSE ),
        '#weight' => $weight,
      );
    }
    $form['#submit'][] = 'exclude_node_title_node_edit_form_submit';
  }
}