How does the orders_total table get updated?

Hi,

I'm working on a zen cart site for a client and I'm having trouble figuring out at what point during the checkout process the orders_total table gets updated. More specifically, there is a module installed that allows customers to pay extra to make sure their order is processed and shipped ASAP. The mod works correct in the sense that the extra fee is added to the order total at checkout and the customer does pay for it. However, when I check the orders_total table the field for this "Priority handling fee" is zero for every customer even though many customers have used it. How can that be? Does the order_total table get updated after checkout is complete? Where does the responsibility for this update reside? Is it the order class, the file defining the module in question, the checkout process, ...?

The orders_total table is updated by the order class (defined by /includes/classes/order.php) during the checkout_process page's processing.