How can we generate AR invoice according to the shipment price and not the price in the SO lines?

The question is :

How can we generate AR invoice according to
the shipment price and not the price in the SO lines?

And I will explain:

we have an item AS9032 with 2 grades A & B

the same item exist in price list twice

Grade A = XX price

Grade B = XY price

What determines the order price
is the list price
+ Grade manually entered prior to
shipment.

The problem is :

We have placed an order for item AS9032 grade
A for 100 units

We have the reservation
putting away quantity of 100 units (Container), and decided on a type A (xx price) ,

then actually sending