Again, I was just saying that 150 comes entirely from the cubic measurement. If you follow the outline instead, you get the slightly higher 70-75 figure you
also see if you look it up. By further removing internal empty spaces, you'll get the figure that you've arrived at by just using the density figure that you've used.
All I was trying to say was "Here was their flawed methodology, and here's how to refine that methodology to be more accurate". Your figure is more accurate, but they're both approximations based on abstractions. That's inevitable when dealing with the theoretical Average Person.
Edit:
1condor12 asked "where are they getting that figure". I was explaining where they got that figure and why it was wrong. We aren't disagreeing here. You corrected them, I explained how the mistake was made, in hopes that the mistake would not be made in the future. I probably could have gone about it better, but here we are.