SKULabs reads your FBA inventory from Amazon and adds up the fulfillable units of every Amazon offer (FNSKU) linked to the same SKULabs item or kit. Amazon's Seller Central often shows each offer on its own line. So the FBA Warehouse total in SKULabs can be higher than the number you see on one listing in Seller Central.
This usually happens after you recreate a listing, convert a listing between FBA and FBM, or create a second offer for the same product. Normally this is expected: you moved to a new FNSKU and still sell the old units. But it can also mean old units are stranded, or a different product is linked to the wrong item.
1. Find the extra FNSKU
Step 1. Open the item and copy its SKU. The Stock panel shows the combined FBA Warehouse quantity.
Item details page: the FBA Warehouse row shows 14 units on hand for SKU ANYSKU.
Step 2. Go to Inventory > Warehouses and open your FBA warehouse. This table shows the FBA inventory SKULabs received from Amazon, one row per Amazon offer.
Step 3. Search the table for the SKU you copied. Every row with that SKU in the SKULabs SKU column is counted in the item's FBA total.
FBA warehouse table: two Amazon offers (12 and 2 units) are linked to SKULabs SKU ANYSKU, so the item shows 14.
2. Fix it
Both offers are the same product: the total is correct. You can sell through the old offer's units, or manage them in Seller Central.
The offers are different products: unlink the wrong listing and link it to the right item or kit. See How to link or relink a listing to an item or kit. Also check the item's Fulfillment SKU (FNSKU) field in Edit. SKULabs uses it to match FBA inventory too.
You can't find the old offer in Seller Central: look under Inactive, Fix stranded inventory and Remove Unfulfillable Inventory on Amazon's Manage Inventory page. For more help, contact Amazon Seller Support.
Seller Central Manage Inventory: check the Inactive and Fix stranded inventory tabs for old offers.