Most people are Not consistent with MN. The most that I can do personally is 3x a week. People use MN off and on sometimes on different months. Looking for an average rate of growth might not be acccurate since you wouldnt know that persons growth rate unless they stated it.
I have personally never seen anyone claiming extremely riduclous growth, but just because it falls with the average, it may be Above average for Them.Also Growth and Retention are two different things. Alot of people do not retain as much as they grow. So their year end photo will not represent all of the inches they gained.
I agree that it is hard to verify, but so are most growth aids unless looking directly at measured newgrowth. Unlike other products where shine may be easily noticeable.