PIP Review and ESA?

It still seems unclear to me. If both the PIP and ESA decision makers are using each others assessments to reach a decision then if they believe there are inconsistencies between both assessments could a PIP decision maker then request another WCA or visa versa? Or is that unlikely?

Thanks Gordon, that's really clear. One less thing to worry about.

I read through the ESA guide, "mental wca mar 18 v28". I'm not sure how this differs from the guide I used early last year, "mental wca oct 16 v24. I can see that from April 2017 new claimants no longer receive the work related activity component. I couldn't work out what else had changed since last year.
What has changed for those of us in the support group? Have the mental health descriptors changed their meaning in some way? If so, is there any information about which ones have changed? Nothing has changed with my illness so the advice worker at the CAB helped me fill in the form using the same information as last time. I did ask if the way we are assessed had changed but the advice worker didn't seem to think so. Am I missing something important here? I keep going over everything again and again because it's so worrying.