I have a client that needs to modify order totals (discounts and free gifts, etc) based on the type of credit card a user is using. I looked at the order total modules provided with zen cart and on the order confirmation page the totals "look" right. I just want to make sure that I am approaching this correctly do I just modify the totals directly in the process function
by modifying the values in:

$order->info['total'] and $order->info['tax'] or will this only modify what's displayed (and not actually modify what gets charged to the buyer's CC)? I've run through the process once and it seems ok on the display, however the receipt that is sent to me doesn't display any changes in the totals and my order history does not show any changes in the totals as well. Is there somewhere else that I need to be making a module to affect the receipts and order history?

I don't have immediate access to the merchant account to check if the total charged was correct (that info is coming) but I just wanted to ask here if I was approaching this problem correctly.


Thanks,
-b