Alternative style doesn't work

vote_up_down_widget$style outputs as vote_up_down_widgetalt instead of vote_up_down_widget_alt
so alternative style doesn't work

function vote_up_down_widget_form($node) {
  $return = '';
  if (user_access('view up/down votes')) {
    $node_type = in_array($node->type, variable_get('vote_up_down_node_types', array()), TRUE);
    if ($node_type) {
      $style = variable_get('vote_up_down_widget_style_node', 0) == 1 ? '_alt' : '';
      if ($teaser && variable_get('vote_up_down_widget_node', 0) && variable_get('vote_up_down_widget_node', 0) != 2) {
        $return = theme("vote_up_down_widget$style", $node->nid, 'node');
      }
      else if (!$teaser && variable_get('vote_up_down_widget_node', 0) > 1) {
        $return = theme("vote_up_down_widget$style", $node->nid, 'node');
      }
    }
  }
  return $return;
}