Hello there, @NStorrs.

I'm here to share with you the impact of updating the inventory items' quantity to your Profit and Loss report.

The change in your inventory items or any adjustments on it is a component in the calculation of your Cost of Goods Sold. This is reported in your company's Profit and Loss report.  Just a heads-up, an increase in inventory will be subtracted from a company's purchases of goods. However, a decrease in inventory will be added to a company's purchase of goods to arrive at the cost of goods sold. You can read through this article for more insights: Adjust inventory quantity on hand in QuickBooks Online.

Also, I'd recommend consulting with an accountant when making the necessary adjustments in your inventory entries. This way, you can make sure that it is properly recorded. 

Let me know if you have other questions about managing your inventory items. I'm always here to help.