I need to fix an inventory items in my POS that were initially set up incorrectly.

The manager that runs my store added a case of stuff that are sold individually and made the base unit the case, the cost of the case she added as the average cost, etc.etc.... TOTALLY screwed my margins, COGS and then did a quantity adjustment! 

I've seen other posts similar and from what I'm gathering, there's no fix for this, a QB F:ck up incapability. If I were to go to all the sales and reverse them, putting inventory back into assets, somehow revert the quantity adjustment, go back and fix (enter) the inventory item and then resell the product, thereby fixing the history that's calculated wrong. I thought if I could revert the revert, the items would refer back to the original customer , but that doesn't work. I tested part of this theory on my own sale,( not the item that needs to be fixed) which when I reverted, it refunded the cost as cash, I then resold it to myself as cash.  Will this work if I revert all the customer receipts, fix the item and then as a one time cash sale, in bulk, resell the item that is now entered correctly?