The tolerances to which these engines are built means they dont need break-in oil.
We tested a E46 at a tuner before work was carried out on it. The car had normal BMW paid services at the stipulated intervals and had over 100,000Km on it, and we tested the compression in each cylinder. The compression was perfectly within factory spec for each cylinder
So the rings were perfectly seated with the normal oil.
With the older engine building technology and tolerances one had to run mineral oil because it took quite a while for the rings to seat, but has not been the case for BMW engines for quite a while now