Since we're the only company in the state that does it, you'll get wide-eyed stares from the lesser shops when you bring this topic up.
What's the big deal? Well, seams are the big deal. In theory, all slabs are dead flat and have no warpage. That would be 'in theory' only, because it is not that way in the real world. In 2cm stone, you can manhandle it a bit to deal with warpage. In 3cm, there is no manhandling. It is simply too strong. Now, we have mechanical devices that lessen the warpage as we install, but that does not guarantee that it will be dead flat.
This is where 'top polishing' comes in. After the seam is set with the epoxy, we then flatten the seam with special tooling. Then, with special tooling and technique, we bring the shine back up to 'factory' levels. You may sometimes see a hint of the seam, but you'll never 'feel' it.
It is a big deal. It is a built in part of the service that we provide.