Hello Nicolas,
we sell acrylic plate. Our customer can give us via the custom field the length and with of the plate.
After this the price of the quarel meter will be shown in the cart as picture showed. We want to offer our customer the option "polishing" of the acrylic sheet. The polishing price is e.g. 5€ per meter. If the customer imput length and width (imput for the plate 500x500mm) the system should calculated the polishing-price ((0,5m+0,5m)x2 = 5€)and give it also the cart.
Unfortunately our developer can not help us furhter. Can you please support us with this challenge?
Thank you for your help.