Can I change the quantities I have already generated on an Amazon shipping plan?
Edited
If you have already approved a shipping plan, Amazon FBA will only allow you to edit up to 5 percent of each Amazon SKU, or up to 6 units, above or below the original amount without incurring fees.
You will need to repeat the shipment and create a new shipment if you need to add more packages.
You can’t add more Amazon SKUs.
See Amazon’s Help Center for more information.