Ive configured Shipping.FixedByWeightByTotal so that up to 20Kg its a fixed price and after that its and extra 80p per kg, this had been working fine on the previous version I was running 3.8 I'm now on 4.2 and it only works for me as admin and not other customers.
As admin I get charged correctly, all other customers when I impersonate them and when they do it have zero charge for postage.
Not sure if its related but countries show twice on the drop down list now as well even though there is only one entry in the database per country.
You can show me your website. Can I try and help you?
RE: "...customers...have zero charge for postage..."
Check that the Roles they are in don't have "Free shipping" selected.
Also check discounts. There is a Requirement called "must be assigned to customer role"
Hi, checked both and no change I did have one role with free shipping but I’ve taken that off restarted and it’s still free shipping
RE: "only works for me as admin"
I assume you set up your cart exactly the same as the customer's cart. Be sure it's the same, since Products can also be marked as "Free shipping".