Actually, I think you know the answer to this better than anyone. Being his parent, you truly understand your child's mind, the things he comprehends and so forth. Now, take your child and work with him at home, challenging him to the max that he can handle. Then, decide what that difference is between his moments of clarity and his SPD challenged mind. The actual points don't matter, I don't think, unless you wish to build a case for DYS in the future. Just my take.