When listing, you have the option to Add to an Existing Shipping Plan. This allows you to continuously add to an existing shipping plan until you’re ready to create an FBA shipment(s) in Seller Central.
Here's how to do it.
1. Click on the Shipping Plan button on the bottom screen of ScanLister.
2. Select the batch of items that you would like to add to the shipping plan. Then select Add to Existing Shipping Plan.
3. Now enter the Plan ID (not to be confused with Plan Name).
4. You can find the Plan ID in your Amazon Seller Central Account. Go to Inventory - Manage FBA Shipments - Shipping Plan.