2 Mandatory Review on PIP?

Hi.

My son has just had a mandatory review for his PIP claim for AuADHD and Dyslexia. He masked all the way through the telephone interview, and when pressed would agree he could do to get the call over, and what I said in contrast was completely ignored. No change -only points for dyslexia. His circumstances have changed since the original application and I am wondering if we are better raise new evidence on the original claim and ask for a 2nd MR rather than go directly to appeal, and then reapply under the new circumstances. Does anyone know if this is possible for PIP? Thank you