Good question. If you cut it you have definitely changed the weight of the club no matter where you grip it but gripping down the club itself still weighs the same you've just shortened it a bit. I guess it could still have the same effect though.
Ping's response to my question about cutting .75" off the shaft: "It is ok (to do), you will loose about 4-5 swingweight points when doing this. Which will make the club feel a little lighter."