BA768 used to leave LHR at 17:00 or later and dinned was served in CE. A flight timed to leave at 16:40 (but in reality taking off at 17:00) getting you to OSL at almost 20:00 local time really should have dinner. This is a very poor enhancement by BA to the evening flight to OSL.
I would agree that CE really isn't worth it on this flight, and probably not worth it at all.