Allow shipping and discount rules to use totals after discounts are applied

Currently when setting up rules for custom shipping methods and discount rules the total used is before discounts are applied, currently it makes no sense if I have a sale and my item is heavily discounted and I offer free shipping at $100 if the customer is only spending $80 on a product that is 20% off. Another situation maybe I want to give a $10 discount on orders over $100 if there is a huge markdown on an item say 50%, the customer could potentially be able to spend only $50 and receive the $10 off.