The landed unit cost field in Kinetic is extremely important. All of the profitability calculations depend on this field being accurate. You can update your landed unit cost for each of your products in the "Product View" page by selecting one of your ASIN's.
Your landed unit cost should include all of the fees and costs associated with your product except for Amazon fees, on a per unit basis. Below is a summary of potential costs to include, you may have additional costs depending on your business.
Manufacturing costs
Shipping costs
Packaging costs
Other fees/costs
All landed unit costs should be calculated at the unit level. This means that if your ASIN includes multiple pieces of products, you should add up all of the costs for each item and calculated a landed unit cost for the entire unit that will be sold.