@nycmusic
I compared the density readings and T-scores obtained on machines manufactured by 2 different manufacturers. I purposefully had switched to a new location as I was not comfortable that the first one had positioned me properly. The T-score for my left femur was the same on both pieces of equipment after a 2-year gap. However, the density readings are drastically different (over 0.5 g/cm2) which means to me there is an inherent difference in the 2 systems to have different densities produce the same T-score.