I really can't see you got 50 actual average. I'm calling shenanigans. The manual is more efficient than the auto... and driving at 50, I reset the MPG average for a 10 mile mobile roadworks... and even that at 50, in 6th gear that was pushing 42... and I've done 2k miles, so arguably my engine is more broken in.
I think you've read the wrong dial imo, above it is the "consumption at present" middle is the average. 50 is borderline impossible at actual sensible speeds and not travelling exclusively downhill, whilst also a tail wind pushes you on... PLUS, the gasps and whispers of your fans willing your MPG to be that high. This is the only way, whilst also travelling at 42 mpg in 6th gear for extended duration.
Short term, you could achieve 50... but on any actual distance... (1 mile or higher) I have my doubts.