Clarification on Using FNSKU with Existing ASINs vs. Creating New Listings

Hello,

We recently created a new Amazon Seller account after our Vendor account was terminated. Initially, I ported over our existing product listings using our UPCs. However, after internal discussions and recognizing that there are third-party sellers (some authorized, some not) offering our products on Amazon, we decided it would be best to move forward using Amazon barcodes (FNSKUs) to avoid co-mingled inventory — especially since our products are medical devices with expiration dates.

I updated our account settings to default to Amazon barcodes, deleted our previous listings, and re-listed the products. Now in our FBA inventory, I can see that our products have FNSKUs assigned, but they are still tied to the original ASINs created under our former Vendor relationship.

In my most recent research, I’ve seen recommendations suggesting that in order to use FNSKUs and retain full control, we may need to create brand new listings. However, I’m unclear if this is necessary in our case. We are the brand owner, and these listings already include updated product information, A+ content, and new imagery that we developed and maintained through our Vendor account.

Do we need to create entirely new listings to use FNSKUs, or can we continue using the original ASINs (now under our Seller account) and still ensure our inventory is not co-mingled, assuming we’re using Amazon barcodes?

Thank you in advance for your help — our immediate goal is simply to get our Seller account live and active with accurate listings and properly labeled inventory.