The last fret? As in it only buzzes right up at the top of the neck, around 21/22 (I can't recall how many frets the SS has). If so, maybe you have too much relief, bowing the end of the neck towards the strings?
Maybe take a bit of relief out which will drop the action at the same time, then raise the action a bit to compensate.
Sorry. I wasn't I clear as I was hoping to be.
Relief is at .010 and .005 as indicated above.
What I mean is that when I fret a note, the string vibrates along its then free length. It is travel (in that free length) I can see and hear the string just catching the highest frets, though none is obviously high.