need to say large pieces of terrain in this case, because barriercades, are scatter terrain, they are still pieces of terrain.
The issues with the rules, is that requires a lot of measuring, and the start point of the measurement is going to change between the two players. Naturally it would be from the center of the object, but alot of time its not prefect, and it can change the outcome. It's not overly a huge issues, just a consideration