Although it looks good, I have to say I'm somewhat confused. Did you actually boost the signal by 27dB at 20Hz? If so, you added far too much boost to accomplish your goal.
Your sub looks like it is naturally dropping off around 35Hz. Sometimes you can locate a sub in a corner and realize some natural room gain. Then you can add a bit of boost (never more than 5dB) to help out too.
Too much boost removes headroom in both the sub and the equalizer. If you have set the input to your equalizer correctly, then a boost filter of ~27dB would cause the equalizer to clip - resulting in the requirement to lower the input level by that much to avoid clipping. This severely lowers usable dynamic range.
Next time you measure it's a good idea to use an end frequency of 200Hz and not 80Hz - (and be sure to only measure the sub without the mains turned on).
brucek