I need to add a surcharge shipping cost for long items.
How can I do that?
I'd like to add a shipping surcharge rate when the product is longer than 100 cm.
I understood I have to create a surcharge shipping type in the shipping cost management and that I have to calculate the rate based on "Calculation".
Then in the Calculations field I wrote: "If (d.length >100,10,0) because I want to add 10 euro to the standard shipping cost when the product is longer than 100 cm.,
but this didn't work at the checkout then.
What have I made wrong?