My meter says 320 kilometres on full tank, but the range quickly adapts (drops) if you drive like 120-130kmh. Consumption per litre also goes from the typical ~4 to 6+.
So, if you drive at 80-100kmh you probably get the 180 miles per tank. If you drive faster, then you dont.
That said I have never filled more than 15 litres, and that was with the fuel light on and 25km left on the range. I dunno how anyone could fit in 20L there.