Dear, Don! SLS – is Signalling Link Selector?. If so, then SLSs (16 ones) are evenly distributed between Signalling Link Codes.
For example, if you have only one SLC in Link Set, it is randomly distributed between all 16 SLS.
If you have two SLC, the first one is randomly distributed between one half SLS and the second is randomly distributed between other half SLS (e.g. SLC=0 – SLS = 0,2,4,6,8,A,C,E, and SLC=1 – SLS = 1,3,5,7,9,B,D,F; – may be other order, it is dependent from implementations).