STBYRUD,
I agree also the figures are a bit wild at times! I think the nose wheel plays a part in the calculations. The reason I have this theory is because I did a smooth landing the other day but the nose came down a bit heavy so the figure I got was 1.7.
I have been told from my father (engineer) that the range is usually beween 1.4-1.7 for normal conditions anything reading 2.0+ is considered a hard landing.