Hello Kristian,
There is really only one way to establish whether it is quantity or sensor associated.
Simply drain the oil yourself, and carefully refill with the exact measured quantity of oil ( quoted capacity without filter).
If you add oil to satisfy the oil level indicator, then you will never know whether it is overfilled or not.
If you can only find a quoted capacity inc. filter, then you will obviously need to renew that as well.
Yes expensive, but you will then have peace of mind.
Kind regards,
Gareth.