1-day 67594 71286 adding break buy cart catch catching code current data determines generator incoming info item link max number1 php position post process promotion quantity quantity1 statement switch url value working

I'm using the Buy Now link for a 1-day promotion and the code generator url is not catching the sent info:

If using a Buy Now link, what is the value of item_cart_position? I ask because I'm using item_cart_position to process the incoming data.

Here is the current PHP that determines which item to process:

switch ($_POST['item_cart_position']) {
case '1':
if ($_POST['quantity1']) {
if ($_POST['item_number1'] == 67594)
$max_quantity = 1 * $_POST['quantity1'];
else if ($_POST['item_number1'] == 71286)
$max_quantity = 3 * $_POST['quantity1'];
}
break;

I've tried adding another else if statement with the Buy Now item_number1 but it's still not working. How can I catch a Buy Now link in PHP?