To piggyback off of what was already said, I also think that 160 is a good goal to have for the September exam. PTing is good for stamina, but revisiting the CC is what is going to get your score up.
I just want to hop on here to say that, at least for me, test day energy is a real thing. I think the bigger concern is making sure you ramp down adrenaline- not the other way around. Stamina wise I was more than fine after pting with 4 sections.
It may be a stamina issue or having to quickly switch gears between sections. The more PTs you do, the better you'll get. You have the skills, you just need to get into the right groove.