I've never actually filled my V40 till the top click, so I can't comment, but I would think from red light till full (seeing that the tank is 62l) you should at least be able to get 50+ litres in there.
I’m not sure why the 8 th bar isn’t lighting up once you have filled your car but do know that 2016 models ( not sure about older models) have two fuel tank options a 40 and a 60 litre option so maybe 42 litres the tank could be full........ did try to fill mine to the top once becareful as it can run down the inside of the wheel arch of its over filled .......Sorry if I'm a little off topic, but you guys seem to know a lot about fueling, so my problem is that I can't seem to fill it all the way up... last time I wainted for the last bar to turn red, then I went straight to a station and went to business... 42 liters.... until the pump clicked, waited a few seconds tried again... a few drops went in and the pump clicked again... repeated a few times, same result. When I check the car it only shows 7 bars instead of 8. Any tips? Sounds like an issue that needs a service, but I'm not in a hurry with all this covid stuff as I'm running out of money xD