I think some people might be missing the point here. The objective of the procedure is to re-introduce the randomness of tracking which was common in the "old days" before GPS etc. SLOPS suggests that each pilot changes his tracking every crossing. Say on centreline first time, 1nm right next time and 2nm right third time. If everyone does this then the likelyhood of having a Rad Alt tripped by an underflying B747 for instance is significantly reduced as is the risk of a head on with opposite direction traffic.