the manual is correct. you need to vary the load so that the pistons fit themselves into the bore. low revs (PER MANUAL) are good cos hi revs cause scoring of the cylinder wall.
so many people talk about this pre-running oil i have to believe it. i have not seen it on any bmw literature (can the previous poster provide a reference that they really do this ??).
historically, two decades ago or so, cars indeed had break-in oil of different viscosity. that needed to be drained, and manual told you to do it.
one last tip: short trips (engine does not reach temp, under 10 mins) are bad. some h20 condenstation always happens and it creats an emulsion until engine heat drives it off. that emulsion is bad for new bearings.
p.s. i have the same car, it SOOOO rules. damn it rules.