If you fill beyond the first click, it may trigger the engine warning light if any fuel gets into the evap system, so I don't go beyond the first click.
With the filler flap at 12 or 6 o'clock, it should fill normally.
My Plus 4 shows full (when filled) but it drops rapidly to 3/4 and then much slower to 1/4.
Last year I did something I don't usually do - I got caught out a long way from any fuel stations, and ran for over 30 miles with the warning light on.............
