You can try customizing the order class and change the order by ... currently it is set to match the way the products were added to the Order based on how the customer ordered them:
Code:
$orders_products_query = "select orders_products_id, products_id, products_name,
products_model, products_price, products_tax,
products_quantity, final_price,
onetime_charges,
products_priced_by_attribute, product_is_free, products_discount_type,
products_discount_type_from
from " . TABLE_ORDERS_PRODUCTS . "
where orders_id = '" . (int)$order_id . "'
order by orders_products_id";