Weight calculation is a handy tool for calculating the wight of the cart item dynamically. Using this value in one of the variety of shipping cost calculation plugins gives a possibility to calculate real shipping rates! 🏆 However UniCPO DOES NOT calculate a shipping cost by itself. It sets cart item's weight dynamically, so shipping cost calculation plugins could use this value! Also, please, notice that not every shipping cost calculation plugin is compatible with UniCPO and this feature. Please, check the section about compatible plugins and themes.