Bird Creek

I was just browsing and looking for a possible river that I may want to run next summer if i travel. I saw this description about a rapid that is like soc-em-dog on the chattooga. I live in Georgia, and i've never heard of it being called a class VI rapid. All the rapid is is a simple boof. I would consider it a class IV. This is just interesting to me, because i thought the international scale was congruent. Granted i did paddle with some 'class V' midwest paddlers on an easy class IV and they continuously got beat down.