Billing based on actual quality

Dear Gurus,

In our client company, they deal in different ore. If i want to ask a question only on sales side, then if their customer wants an ore with some qualities as captured in the variant configurator, like:

Character 1 = 65%

Character 2 = 2%

Character 3 = 12%

The price for this combination is (say) 100$/ton

But since this is ore, chances are that always that is not what comes out of the mine. So when it comes to doing delivey the quality changes to something like:

Character 1 = 62%

Character 2 = 1.67%

Character 3 = 14%

The price for this combination could be (say) 92$/ton

This information is only known at the time of delivery and this information has to be captured only at the delivery level and cannot be captured back in sales order, since for each sales order, there can be multiple deliveries, each delivery with different quality. But as per rule, customer has to be billed as per the Quality he receives. That is:

Sales Order SO1234 - Quantity 100 tons - Quality Combo1

Delivery DEL567 - Quantity 15 tons - Quality Combo2

Delivery DEL568 - Quantity 20 tons - Quality Combo3

Delivery DEL569 - Quantity 18 tons - Quality Combo4 and so on . . . .

One small deviation is sometimes when the Quality analysis is not received on time, billing has to done on the quality as available in the sales order and the difference, if any, will be adjusted through Credit / Debit notes.

If someone can throw some light on this and give me a dynamic solution possibilities, that would be just great. Would appreciate all you help.

Best regards

Venkat - Hyd