This solution applies to the following problems:
Orders can be fulfilled by picking random, extra, or mystery items.
Products that can be picked to fulfill these orders are overselling or have inaccurate stock.
Store any products that can equally satisfy an order in a separate physical bin or location.
Track the total quantity of products in this location using a miscellaneous SKULabs item.
Fulfill orders for mystery items using the miscellaneous item stock quantity.
Steps to implement:
From the Inventory page, create a new SKULabs item. You can think of this as a misc. item.
Link any listings for mystery items to this new misc. item.
Use the deduct tab to deduct stock from the various products that could be picked to fulfill orders for mystery items.
Use the receive tab to receive an equal quantity of stock into the new misc. item's inventory.
Pick orders for mystery items using the stock from the new misc. item location.