Tim Hewitt said many times that graphite shafts today ( this was 6-7 years ago) are so stable in the tip that they do not require tip trimming like in the days gone by. He would joke that companies would actually publish them because if they didn't that people wouldn't believe them and they would be flooded with calls asking what the tip trim was.
so unless you really load the shaft at impact , are strong with a very fast swing speed such that you find that untipped provides too much launch angle, no need to tip. ( my experience as well) remember trimming shafts at the tip is for trajectory control