McLane retailers are part of the group Mable buyers who have landed costs. Mable Brand Terms & Conditions 6(b) outlines the concept of "Landed Cost" and the calculation process, and this article on Adjusted Base Wholesale Prices provides more detail as well.
Landed costs are a way to include shipping costs in the price a buyer sees for a product. McLane retailers and Mable cover 100% of the shipping cost for McLane orders, and brands are always paid out on what you set your pricing to. McLane retailers only see landed costs on their end, which is why pricing on the packing slip for an order may differ from pricing on the Purchase Order.