The 'New Orders' section simply displays the most recent orders - It doesn't necessarily mean that they're "new".

If you are concered about semantics, you can always change that text to read "recent orders" by editing admin/includes/languages/english/index.php and changing
Code:
define('BOX_ENTRY_NEW_ORDERS', 'New orders:');
to
Code:
define('BOX_ENTRY_NEW_ORDERS', 'Recent orders:');