Weight in final order not working

I have a formula for calculating the weight of the product relative to the ordered area. The plugin correctly calculates the desired area (length, width) and the total weight relative to the entered weight per square meter. It correctly displays the values ??in the cart.
However, the final value of the total weight after completing the order still shows the standard weight entered in Voocommerce per square meter, and not the new one from Uni CPO calculations.
Where am I wrong?
Is there a way to update the total weight of the product at the end of the completed order, as shown from Uni CPO?