Well we already know that these numbers are massaged as it is. I don't think the number is completely fictitious, but the rules of what constitutes a member are done by the Org.
In other words, members are basically a calculation of the month where the most people report. Is this a truly honest assessment? Well no...but the Org calls the shots on how it is calculated. If tomorrow they decide membership is based on a slightly different calculation that somehow favors them, they will do it so that the number look somewhat palatable.
In other words, we really don't have an unbiased way to know membership.