When I was a loyal dub, I assumed all these numbers were absolute "gospel." This being "the truth" and all. Now I have a different perspective.
It's clear that the rank and file massages its own numbers. That 9.4 "average" hours per month would be nearly impossible to attain for the average publisher, with a full time job and kids, if it were truly an honest accounting of the number of hours, in minutes, spent witnessing to people. A typical 9.4 hour report would look like this, in my experience:
Study with the kids (which we didn't actually get around to this month, again, but we can't just stop reporting it, right?): 4 hours. Oh, wait, there were five Mondays last month and that's the night we study, or would have studied, if we had studied, so: 5 hours.
Two Saturdays in service, time spent in door-to-door work, 30 minutes total; time spent driving around, stopping for coffee break that turned into breakfast and happy hour, and including the 30-minute meeting for service at the hall and post-meeting social time (because, hey, I had to be there so it's part of the job), 2.5 hours each day = 5 hours.
So that's 10, which is close enough.
My point is, in this kind of "culture," the corporate numbers aren't going to be vastly more reliable than those posted by the front line workers.