You're probably somewhat correct Don ... but I'll bet that the differences aren't much ... unless of course they are graded by a point system. Each point equates to an incremental increase... which is why some dealers are in favor of 70 and 100 point grading systems. I was pleased that Rene did not resort to arbitrarily assigning grading numbers on his Thunderbirds. Pick whichever one you wanted... same price; $25.