While charging at the fast charger on August 31 I went to take a closer look.
I found the payment machine with the tariffs. Since you can pay right there, it seems like it's possible to park and pay even if you aren't really an ABB visitor.
The row of chargers outside have their parking spaces match the PLUG'N'ROLL names. There's also a PLUG'N'ROLL sticker, but no QR codes for ad-hoc payment. It only says to use the RFID.
Inside the parking in the area marked for ABB employees there are still 2 DC chargers and another row of AC chargers. On the DC charger there's a sign saying that starting November 26, 2022 the chargers would be private. It seems to be the same sign that was posted on the outdoor DC chargers in the past.