Default/Auto Shipping Method not updating when removing last item from cart

[axcesstech]

Running VM 2.0.18a, Joomla! 2.5.4

My customer's site has the following four shipping rates set up:

1. Standard Shipping
   Country: USA
   Minimum number of products: 1
   Minimum order amount: 0.01
   Maximum order amount: 100
   Shipment Cost: 12
2. Standard Shipping
   Country: USA
   Minimum number of products: 1
   Minimum order amount: 100.01
   Maximum order amount: 200
   Shipment Cost: 18
3. Standard Shipping
   Country: USA
   Minimum number of products: 1
   Minimum order amount: 200.01
   Maximum order amount: 300
   Shipment Cost: 24
4. Standard Shipping
   Country: USA
   Minimum number of products: 1
   Minimum order amount: 300.01
   Maximum order amount:
   Shipment Cost: 25
   
As I add products to the cart, the shipping goes up based on the cart total, as it should. As I remove products, the shipping goes down, based on cart total. That's perfect.

However, when I remove the last product, the shipping charge remains. It remains whether it was $25 at the time, or $12, or anything in between. I found a post (http://forum.virtuemart.net/index.php?topic=104616.0) that suggests this is by design, but since the cart values do not match any of the available shipping methods, I would expect the shipping information to be cleared out when I remove that last item.

I tried adding a fifth shipping model the same as above, but the minimum and maximum order amounts were set to zero and the minimum number of products ws zero. But even when I deleted all the items in my cart, the shipping did not change to this model.

If my cart is empty, and none of my shipping rates match zero products at zero charge, shouldn't the shipping default information disappear, since none match my cart values?