function get_order_total() {
    global $order;
    $order_total = $order->info['total'];
    // if we are not supposed to include tax in credit calculations, subtract it out
    if ($this->include_tax != 'true') $order_total -= $order->info['tax'];
    // if we are not supposed to include shipping amount in credit calcs, subtract it out
    if ($this->include_shipping != 'true') $order_total -= $order->info['shipping_cost'];
    $order_total = $order->info['total'];
    return $order_total;
  }