Unfortunately, I don't think that will work in this situation. (That is a cool feature, though.)
I have two conflicting requirements.
1. I need to calculate volume discounts and override the amount.
2. I need to allow orders with multiple products of different qualities.
1 will work with the Buy Now button overriding the price, and #2 is essentially what the cart is made for - but there it has no mechanism to override the price.
That's why I was delving into the form fields to see if I could create my own order form and pass the fields to e-junkie.com/ecom/gb.php?...