Scalloping also affects the GS I'm led to believe.
One can see the ICAO ILS Permitted Guidance Errors in an interesting AIAA paper
here amongst other places.
Of course, whilst approaching the limits of the certified area, I've always thought the GS onto RW 14 @ AGP was a classic illustration of this. I've seen some interesting altimeter readings at various distances from the field inbound.
Errors that neither temperature corrections or altimeter errors would seem to explain.
