I updated my product costs for 2021 in Product and services, QBO re-calculated my COGS for 2020. This forum says past invoices should not be affected by cost updates.

in QB inventory has to be purchased before selling it, that purchase establishes a cost.

If you do not purchase, then the cost you enter on the item screen is used. And as you can see since there was no purchase it tends to mess things up. Of course that assumes you use inventory type items. And if you do then the balance sheet is also wrong for the account inventory asset.

Thanks.  I am finding that QBO is not ideal for distillery accounting when all the value add is done in house and items such as grain, yeast are bought 5 years before bottling and potential sales.  I don't even know my costs until we bottle and we know what the angels' share is.  I think I have a work around when bottling happens though and I know my final costs for the batch.