Availability:::: "Should Arrive By Date"

This code DOES NOT

Take Location into account
Take shipping location into account

This code takes "Availability" which is an exact number of weekdays AND "average" shipping time together, and adds it to TODAY.

I ship only in the USA, so I add the maximum amount of days transit time can take to the amount of days it takes to ship out. (5)
So if a product takes 3 business days to ship out. I make availability "8". Then the result on the products page is 8 business days from today.

avalability.tpl
<?php if( !defined( '_VALID_MOS' ) && !defined( '_JEXEC' ) ) die( 'Direct Access to '.basename(__FILE__).' is not allowed.' ); ?>

<?php
$DeliveryDate = date('mdY', strtotime("+$product_availability Weekdays"));
$EDD= $DeliveryDate;

$mo = substr($EDD, 0, 2);
$da = substr($EDD, 2, 2);
$yr = substr($EDD, 4, 4);

$DDD = $mo . "/" . $da . "/" . $yr;
?>
<strong>Should Arrive</strong>
<?php
echo $DDD;
?>