Is there a way to manage customer inventory that has already been invoiced

with some customers we invoice a large amount of goods at the start of the month and during the month we do the deliveries. Currently when we invoice them the entire inventory is removed from the system and we need to manually track the deliveries and remaining quantities. However the inventory is still at our warehouse. We need to invoice them in advance because that is the only way they can lock the price for the invoiced quantity.

23D