When you create a shipping plan, you can select one of the following inventory inbound placement options:

• Minimal shipment splits: You can send your inventory to the minimal number of inbound locations, generally to a single location, and Amazon will spread inventory across thier network on your behalf, for a fee. The fee may vary by inbound location—for example, there may be higher fees for shipments sent to locations in the West versus other parts of the country.
• Partial or Amazon-optimized shipment splits: Send your inventory to multiple inbound locations yourself for a reduced or no fee. The reduced fees will depend on the number of shipments and inbound locations that you send your inventory to. For instance, if your shipping plan qualifies, you can select the inbound placement option to send your inventory to the optimal number of inbound locations recommended by Amazon, generally four or more locations, and pay no fee. If you select the placement option in which you send your inventory to a partial number of inbound locations, generally two or three, you will pay a reduced fee.

The availability of these inbound placement options is based on several factors, including the product types and quantities that you have in your shipping plan, your existing inventory levels across Amazon's network, and the location of customer demand. 

When you create a shipping plan, you’ll see a fee estimate for each available inbound placement option. You’ll be charged the FBA inbound placement service fee 45 days after your shipment is received by Amazon, based on the inbound location and the quantities received.