Buying Make content in drop downs on order form dynamic.

Please note, I will make payment only after I see a working example

I have an order form for ordering firewood, you can see an example here:
http://paulbunyansfirewood.com/test/
I have also attached the plugin that I created for wordpress if you want to have a look. As you can see the shortcode [woodorder_form] displays the order form on a page.

There is a discount for ordering at least 1 cord of wood.

So if you look at the first "aligator juniper" it shows in the drop down:
1/4 cord - $120
1/2 cord - $235
1 cord - $400

However, if they order 1/2 cord of another wood as well and 1/2 cord of aligator juniper above, then instead of the 1/2 cord price of $235 above, the price is adjusted to only $200 which would be 1/2 of the full cord price of $400 since they are actually order 1 full cord, just 2 different types of wood.

I have all that done, all the prices adjust automatically and are discounted when the total order equals at least 1 cord. So it could be 4 different orders of 1/4 cords and they would all 4 be discounted since it totals 1 full cord.

If you place the order it recalculates the discount and sends the correct amount in the email notification and is also displayed on the page upon form submission, it all works.

I was wondering if it would be possible to update the price on the drop down on the form as new items are selected so the customer can see the discounted price as they add more items?

Right now they don't see the discount until the order is placed, then the discounted amounts are displayed on the "thank you for your order!" that is displayed upon form submission.
However, as things are added the price on the drop down items still show the higher price.

Someone else created this and I had it working before but I screwed it up or it could have been a WP update

If this is possible please let me know, what it would cost and a time frame and what access you require?

Thanks!
-George