There you go, looking better. Just to clarify did you have the receiver in stereo mode? I only ask due to this statement "I did turn off stereo".
Now that you are getting the hang of it for your next reading I would look at changing the smoothing to 1-12th and end your graph around 100HZ since you are not getting much past that.
Also, just to give yourself an idea of what happens when you move around in the room. Move the mic to different locations and take a measurement, save it, move to another location, measure, save, etc (do not change the master volume level though). Than you can load the saved frd file(s) and compare different areas of the room and what kind of response you get.