Just a few tips:
Don't smooth measurements below 200 Hz.
Present your measurement graphs with a vertical SPL scale of 50 dB. The vertical SPL scale in the graph presented is 230 dB.
The phase scaling for the graph should be set to +/- 360˚. The phase vertical scaling as presented is set to +/- 720˚. Phase, when presented wrapped, will not exceed +/- 180˚.
When taking screenshots, don't crop off the scaling as it makes it difficult to interpret the graph with the scaling cut off. Use the camera icon on the top left of the graph to generate a screen shot.
Examples of the same measurement with different presentations:
Unsmoothed, unwrapped phase, 50 dB vertical SPL scaling, 1800˚ to 0˚ phase scaling:
View attachment 242203
1/6 octave smoothing, wrapped phase, 230 dB vertical SPL scaling, +/- 360˚ phase scaling:
View attachment 242204
The second one looks pretty good, like the cute blonde at the end of the bar after you've had a few shots. Reality is much different as you get closer.
The vertical dashed lines in the phase plot indicate a complete 360˚ rotation of phase when the phase plot is presented wrapped. Unwrapping the phase—as is plotted in the top image—indicates its 'true' nature. The scaling of the phase plot when unwrapped needs to be changed to view the entire plot.
What you are seeing is 'normal' for this frequency range. In the absence of the dips in response caused by what is probably modal behavior of the room, the phase plot would actually be a fairly smooth line. Example below:
View attachment 242205