Custom address field is not added to every country

Hello,

I used checkout field editor to add a seperate house number field to my checkout form, as some customers tend to forget to fill in the house number when not explicitly asked.

Now the checkout field for Dutch customers is right, but for our Belgian customers it’s still just the one address field. How can I make sure the form is also updated for other countries?

The page I need help with: [log in to see the link]