I fiddled with the numbers and drawings in the spec sheets and installation instructions too and couldn't figure it out. Maybe just ignore it, leave 2" behind the refrigerator and a 2" gap above the refrigerator and call it a day.

But explain this: The refrigerator is 630mm deep. The drawing shows it 675mm from the rear wall so the difference is less than the required 50mm gap. But there's also this note, "*The appliance depth is increased by approx. 9/16" (15 mm) for refrigeration appliances with wall spacers installed"

Who knows?

My interpretation would be that the air gap at the top of the cabinet across the entire refrigerator width would have to be at least 46.5/30 = 1.55 inches. I'd go for 2 inches, minimum. Or, if the cabinet(s) actually attach to the ceiling (zero effective gap), then a 2 inch gap between the cabinet and the refrigerator top would be required.

Also, the illustration shows a case where there are no side gaps; the air flows under, up the back, and then out across the ceiling. I think this unit is intended to fit neatly into a slot with minimal gaps, but venting above has to be achieved. Side gaps might be counterproductive to the desired flow, as air across the bottom will help evaporate water from the defrost tray.

@kaseki: "Side gaps might be counterproductive to the desired flow, as air across the bottom will help evaporate water from the defrost tray."

Per pages 22-23, a gap is only required if the refrigerator's hinge side is next to a wall.

Call Miele and ask them. There are Miele showrooms as well as the company itself.