Interesting. I've never had issues taking a car from a different section, but decided to look up my most recent confirmation email (May 2021)...
Follow the signs for ground transportation. The Hertz pick up area will have designated signs and a shuttle will take you to the rental location. At the rental location drop off, Gold members can find their name on the Gold board straight ahead to find their stall number or assigned canopy. Standard reservations will go to the main counter inside the customer service building to be processed.
Based on that it can be argued that if you are assigned PC, you have to go choose from PC.
Hertz's website also suggests something similar
It does seem like they're trying to imply that you can't go lower anymore.