There seem to be 2 sets of figures for hg etc. The older ones commonly quoted are way above any score you can get on the new tests though and I don't think they are valid for kids tested today. It is tricky though - I looked at my son's 158 and thought "well it isn't 180 is it?". But maybe it would be if he was tested on a test that measured that high. I eventually decided if he meets the Davidson criteria he is PG.