Subtotal after discount

[willemerson]

I am using Advanz's Volume Discount by Category module. I am also using the ShippingSuperMod. My problem is that we offer free shipping on orders over $250 and also offering volume discounts. When a customer orders $260 of stock, gets a 20% discount based on the categories, his subtotal is $208 so he should not get free shipping. But Merchant sees the subtotal as $260 and that is what ShippingSuperMod uses to decide the shipping mehtod. Is there a way to get the discount figured into the subtotal before the shipping method is calculated? Do any modules do this?
Thanks for any help,
Will Emerson
Livelihood Technology