I think the reason computer grading would "fail" as it would give an absolute answer. I think it could be programmed to detect wear. I doubt the TPG companies want to know that though. Also, if they had a computer program giving computer generated grades, it would be troublesome in court why the assigned grade starting deviating........ In short, TPG will not have it since it would take away their ability to grade as they wish, weakening or strengthening them as their business model wishes.