It's winter and you don't want lots of cold oil in the engine to delay warm up.

I can't believe taking that 'precaution' will make any perceptible difference to the delay before the heater emits warmth. But each to his own. I prefer my oil to be nearer the top mark.

Not all of it. Pour one litre into a spare one litre bottle for top-ups and use the remaining 4 litres to get mid way between min and max mark. It's winter and you don't want lots of cold oil in the engine to delay warm up.

Good grief, I find myself agreeing with John F! It's exactly what I do, as manufacturers usually recommend it. The only time I top up to max is in a known oil burner.

IIRC a Japanese car factory worker suggested the same, thus saving half a litre or so for each new car. He was awarded an enormous sum.