Good, that looks like a useful increase in LF. I would encourage use of Dirac Live to generate a bit more. Or a Sub, dunno about you but I need a solid 30Hz to Mix or Master. The B&K or Harman Target Curve would greatly help translation from your almost anechoic space.(Similar to mine 150mS)
As John said RT60 is overwhelmed by Modes at lower frequencies. Your 1/3 Oct Topt has a distinct peak, but really 450mS or so is not at all long. The EBU Critical Listening Spec allows 400mS.
Looking at a 1 Octave Topt your room decay appears exemplary, albeit on the dry side.
Your Waterfall viewed with a somewhat stringent 50dB vertical range, shows your modes, but there are a few and really nothing much to worry about. Again Dirac Live would tidy these up nicely for you. It would also pull down your prominent mids. BTW, it is important not to stand near the mic when measuring. B&K advise that this can cause anomalies of up to 6dB around 400Hz.
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