Hi AndrewC65
Yes.
And your Inventory account on the Balance Sheet will also be wrong. Suggest you discuss remedy with your accountant/tax adviser. No guarantees editing the invoice will use the correct COGS anyway. Rather than editing hundreds of invoices, General Journal from Inventory to COGS will achieve the same thing - you just need to manually calculate what the COGS should have been.
You should also ensure the Inventory Value Reconciliation Report is 'balanced' - any discrepancy means future COGS may be incorrect. Anyone using 'I Inventory' on MYOB must regularly review this report and identify cause of discrepancy and rectify - esp given the COGS issues with MYOB.
Regards
Gavin