First PIP application

After 7 years of declining mobility and autonomy, I’ve made my first application for PIP. After 3 months waiting and a brief call from a nurse assessing the application, the decision is imminent.
What is entirely unclear is how the ability to move about and do things, which massively fluctuates through the day, will be assessed. So, one hour after taking L-Dopa medication, most things including walking do not present a problem. However three hours later, I’m staggering about like a drunk and can barely get to the toilet. This pattern repeats four times a day and since I am now on a high dose of dopamine the consultant is reluctant to increase further.
What I suspect will happen is that they will justify a lower payment using some form of words that is inaccurate, evasive, impenetrable and I will have to appeal. And then stress will build up, having to challenge the system.
Any advice or insights welcome…