How to calculate your per-unit shipping cost
With a focus on a single SKU, consider all your shipping costs including 3PL warehousing or other logistics costs. Divide that cumulative total by the number of units ultimately delivered to Amazon. This is a per-unit ship cost to enter into HelloProfit for that SKU. If, however, you use Amazon's partnered carriers from either supplier or 3PL, those costs are come across in the Settlement Report under the merchant (not against an individual SKU). So to preserve most accurate merchant-level reporting, do not include Amazon partnered carrier ship costs against individual ASINs.
Remember: HelloProfit is flexible enough to let you enter different shipping costs for different marketplaces! Calculate your per-unit inbound shipping cost if different for various marketplace locales, and enter it into the appropriate marketplace in the Product List, as shown in the screenshot below.