From the factory, the breather tubes are set up in some way through VSVs to minimise the pressure across the SC end seals. This means that less oil is sucked through while the manifold is at vacuum. I'm not sure exactly how they control it or where the VSV is connected, though a good Google may shed some light (I remember reading up on it once).
However you can just bridge all the breathers together. I've run an SC12 like that for about 2 years without problem.