1). If the original invoice can't be cancelled (already paid, cross-period implications etc):

We will need to set the Commodity Code to map to __.6000; this is the same account that the accrual from the GRN would have debited against, once it is posted. This is the only option for processing a credit if an invoice has already completed a line on the order. 

This is the G/L mask field on the commodity code:


Reasoning behind this is that, if the order is not complete then the cost mapping follows this route: 

Invoice/credit < Order (quantity x price) < __.6000 

With the completed line we mimic the setup from Stock Configuration, where the the stock account in ST Config is set: 


And the cost will credit following this route: 

Invoice < __.6000

This is the easiest way to process the price difference. There is an alternative but it is more long-winded, and the effect is the same. It depends on the status of the invoice at the time of processing the credit

2). Second Method (Original invoice still outstanding, line on order not complete)

For this to work we need an outstanding accrual on the line; best practice for the following method is to hold off processing the invoice, and then process the credit first as a Balance Line. This means that when we process the invoice, we fully match against the incorrect price, and at the same time match against the credit balance line.

Processing a Credit Line against an outstanding accrual

I'm using this order to demonstrate this in Learn because none of the lines are fully invoiced and are therefore still open: 


Line is GRN'd:


I will process and post the PL invoice unmatched to any of the order lines as I expect there is a credit. In scenarios where there is an invoice matching query it is advised to un-match the lines and mark the invoice as registered to allow room for the credit note to match, for both transactions be paid at the same time. Of course this depends on what the situation allows and the timescales of receiving a credit note from a supplier compared to how fervently they are chasing for payment. In situations where paying the invoice is more important than the "cleanliness" of the accruals the first option is suitable.

To register the invoice, I change the "Distribution Type" to "Registered":


This status can also be incurred if an invoice is posted with a Matching Imbalance

I post the invoice, and can see against the PO that we have a registered invoice 


I will now enter a credit line against the order. The idea here is that the credit value with reduce the accrued value in the Stock Account, because the invoice will be costed against the accrued line for the original order value.


This will require a GL commodity code against the stock item that is being credited, because we aren't touching any quantities to generate the credit value. As per the accrual process, the accrued value is a multiplication of the order price and order quantity. We do not have a credit quantity in this instance.

The Stock GL commodity code mapping should be the same as the GL Mapping for the stock account in ST Config (usually __.6000) 



Back on the order screen, we can see there is a credit line for the entered credit value:


Once the credit line is matched, we can go ahead and post this. Doing so will reduce the cost in __.6000, but at the same time we leave the order in the original state. This would also work if the original line is complete, if I had decided to fully match the original invoice. Purely depends on timescales and when the credit note is received compared to the invoice

Credit posting details:


I will now cost the invoice to match against the outstanding order line to close the order:



And enter the internal reference which will pull in the account code for me:

Fully match the line and post the invoice costing:



Posting this invoice will debit the invoice value to the Receipt Control, __.7819. The GRN that was booked in prior to processing the invoice will debit the Stock Account __.6000, and credit the Receipt Control:


If we run a GL enquiry we can see that the costs relating to this order for the March period are (Accrued value - Credited value), 2,121.31 - 287.50. I have attached the GL transaction report showing these postings in the 6000 account.


In which order the invoice and credit are posted for price differences, it doesn't really matter. Again this would likely depend on the timescales relating to the supplier's process in sorting these transactions out their end 

Exceptions to this rule 

If the invoice isn't paid you could work backwards - cancelling the invoice, unbooking the GRN quantities, and changing the line price. In that scenario it would be recommended to attach the credit note to the invoice record to it is clear to auditors that we have processed a credit without specifically posting a credit to the Stock Account. Sometimes the supplier will rectify the invoice their end and issue without a credit note; amending the order is suitable in that instance too.