Inventory Tracking Question

When I purchase items to resell, I buy them in bulk quantities and repackage them into smaller quantity packs.

For example:

I buy a case of 100,000 toothpicks.  I sell them in packages of 100, 1000, and 10,000

BUT and that's a BIG BUT

I don't package them until I get the order, so I don't have a set number of 100 packs or a set number of 1000 packs because I have no idea how many of what package my customers are going to buy.

I have it set up as follows:

Product:  "Toothpicks"

     Product Variant:  "Bulk"  - Track inventory for this product = 100,000

            Product Variant Attribute:  "Pack"

                   Product Variant Attribute Values:
                         "100 toothpick"
                         "1000 toothpick"
                         "10000 toothpick"

So when one 1000 pack is sold (which to the customer is Qty 1 of Product Variant Attribute Value "1000 toothpicks"), I want the program to decrement Product Variant inventory to 99,000, not just reduce it by 1.

Is there some way to handle this in nopCommerce as it's set up?

Another question:

If I set my inventory of a Product Variant to 10.  Then try to add qty 11 to my shopping cart, it puts up a message

Your quantity exceeds stock on hand. The maximum quantity that can be added is 10.

That's fine and dandy, however, if I add say 3 of the item to the cart, then go back and try to add 8 more,  It beeps at me and displays the message,

Your quantity exceeds stock on hand. The maximum quantity that can be added is 10.
  
But wait, I'm only entering 8,

Shouldn't it say

Your quantity exceeds stock on hand. The maximum quantity that can be added is 7.

Or the verbage should change to something like:

The total quantity in your cart will exceed the available inventory of 10.

steveeb wrote:

In Administration > Content Management > Localization > "Select language", edit the value for Resource name "ShoppingCart.QuantityExceedsStock".

Original text:
Your quantity exceeds stock on hand. The maximum quantity that can be added is {0}.

Change to:
The total quantity in your cart will exceed the available inventory of {0}.

.