Visited on July 23 and charged with M-CHARGE RFID, no issue.
There are M-CHARGE signs at every turn, but only one is truly needed at the fork between 2.UG and 3.UG directing you towards 2.UG (there's no 1.UG). The other signs on 2.UG aren't strictly needed because there's a single driving loop and you cannot miss the chargers.
The signage around opening hours is confusing. Based on what is written on the payment machine, it seems to be open 24/7, as there are tariffs for those times (now even more expensive than the tariffs I had found online previously). But I also found a sign that says the parking closes 30min after the store, and it sounds like you can exit anytime, but perhaps no longer enter after that time? 🤔
I still see a session every few Sundays, and there are sessions started in the evening after closing hours but even more rarely than Sunday charges. So I still assume that it's possible to enter at those hours as well.
I don't really want to go pay 6CHF just to verify if the parking is open one evening, but if I get the opportunity I'll at least go check whether the curtain is open or not at those hours.
There's a good possibility that the parking could be "impossible" to close if there are also private parking spaces, then the ramp has to stay open, and they have to open the gate or you'd end up stuck at the bottom of the ramp outside business hours.