Wow, that has got to be quite a challenge with HG++ PRI scores and average VCI & others. Poor kiddo must be dealing with some major roadblocks. FWIW, my one dd with ADD tested much lower on WMI and PSI as well but I'm not sure if they are truly low so much as impacted by ADD. She's seriously fast, but she makes so many mistakes that PSI probably came out low due to mistakes not actual speed.

Study Strategies for Accelerated Learners