And yet, is ok to fly from Spain to Germany in a single with an engine shut down at night,...
Not with a single word did I say that this is OK. I wrote about the incident (which in any decent company would have been the last flight of that pilot) to show that the most shaken down piston twin can carry you for another 1000NM if necessary. Like in the middle of a stretch of ocean at night, which is what this whole thread is about.