We run Sage X3 Update 9 Patch 9.

The cost of a product we buy is going negative.

This occurs from time to time because the product is a by-product- sometimes the supplier can sell the by-product, but other times they have to pay us to take it.

Depending on how extremely below zero the costs go, we may even start charging our customers a negative price. 

This will occur in both back-to-back and stock orders.

Can we support this in X3?

Thought process;

(The following all reads bizarrely to me, but here goes...;)

1. We raise PO to supplier with negative cost (-$20/ton)

2. Supplier sends us their invoice with negative cost (-$20/ton)

3. Supplier pays us based on their (negative) invoice. Is a supplier invoice therefore handled by Accounts Receivable rather than Accounts Payable functions in X3?

4. We receive goods into inventory at a negative cost (-$20/ton). Average Unit Cost (AUC) goes negative.

5. We create Sales Order with negative gross price (-$5) and negative cost ($-20) to Customer (Margin = +$15)

6. We create Sales Delivery with negative gross price (-$5) to Customer.

7. We create Sales Invoice with negative gross price (-$5) and negative cost ($-20) to Customer (Margin = +$15) 

8. We pay Customer based on our Sales Invoice with negative gross price. Is our Invoice to Customer therefore managed by our Accounts Payable rather than Accounts Receivable functions in X3?

Is this high level process supportable/logical/sensible in X3?

Steps 3 and 8 are standing out to me the most in consideration of "How will that work?"

Any advice would be appreciated. Thanks in advance.