I have a cart with swguy's "Big Chooser" order total module installed to set up some discounts. That's working just fine.

My table rate shipping (by price) is not observing the discounted total. If the discount module brings $150 of merchandise down to $100, the shipping rate is still calculated based on the $150 price.

Where can I find the code that the table rate shipping module uses to calculate the order total, so I can start working toward post-discount totals?