To be hoinest, I always tune the ILS myself.  But once I forgot and noticed that the FMC had already tuned it to the correct frequency. I don't know how far out it does this but it is plenty far enough out for it to work correctly.  Neil is probbly right.

Also, you should be shooting for more like a 30 degree intercept angle instaed of 45 degrees.  Much more comfortable for the passgengers.  This is ATC will try and do.