That would give you 2h10m on a paid period of 2h.
2h41m seems excessive to me.
The extra time is to allow the sorts of things you refer to.
If you can substantiate the time “looking for parking” this may help, because there are cases and judgments which explicitly state that this isn’t actual parking time. But you need to substantiate spending 30 minutes driving around looking for parking plus the 10 minute “grace period”. On the face of it it’s not easy to believe. But I’m not the person you need to convince. I can’t imaging personally spending 30 minutes driving around a car park looking for a space to become available, but I’m not you.