Is there a method of auditing the Cost changes for a Manufactured Item and its Components?

The Auditors are asking when and why the Cost of an Item changed. We can see the various changes in the cost as a result of a Cost Roll (P30835) and without any inventory on hand there is a Cardex entry. Additionally when the Cost was rolled and then rolled again there must have been a component in the BOM that had its cost revised and justified the need to roll the item a second time. But there isn't any audit showing the Cost revisions of the components nor the product.