Don't forget that every dyno is different and can be adjusted by the operator to indicate lower or higher power outputs (I assume that that feature is so it can be calibrated). I suspect this is something that is done by companies making slip-on mufflers for IC motorcycles to show that slipping on a loud muffler will give your bike more power. Just spin that dial on the dyno and more power will appear.
I might add that the same thing can occur with speedometers. I discovered that the speedometer on my GPR-S provided a 20% higher speed than the actual speed (as indicated by those radar speed check signs). I found a small button at the back of the display that could be adjusted to change the base settings on the instrument to get it to read anything that you wanted. So I adjusted it to accurately reflect my true speed and distance traveled.
I am not saying that this dyno is reading low, but that one dyno can give different power readings compared with another. It all depends upon a lot of variables, some controlled by the operator and many out of his control (such as built into the machine and wear or maintenance related). I wouldn't be too concerned about the actual power reading unless you can get a get another bike on the same dyno and compare both results against each other.
