your code to set the ship type variable is not correct.
on the confirm page, you have:
<?php
if (!session_id()) session_start();
if("" == "") {
$_SESSION["ShipType"] = "".$_SESSION['ShipType'] ."";
}
?>
this is setting the ship type session to be equal to the ship type session, since it hasn't been set yet, it wont get set this way. you need to use the ShipType POST:
<?php
if (!session_id()) session_start();
if($_SERVER["REQUEST_METHOD"] == "POST") {
$_SESSION["ShipType"] = "".((isset($_POST["ShipType"]))?$_POST["ShipType"]:"") ."";
}
?>
also change the hidden form element code to be consistant:
<input name="shipType" type="hidden" id="Shipping_cost" value="<?php echo((isset($_POST["Shipping_cost"]))?$_POST["Shipping_cost"]:"") ?>" />
should be:
<input name="ShipType" type="hidden" id="ShipType" value="<?php echo((isset($_POST["ShipType"]))?$_POST["ShipType"]:"") ?>" />