Ermz, how did you notice the null and the massive peak in your spectrum? With an analyzer playing one of your mixes or with a measurement mic and a dedicated software?
I'd say you are over-thinking things. Just mix the low end slightly different to compensate, and do reference mixes until you get it right. 100% detail at 100-160hz isn't going to make the difference between Andy Sneap and no-name-engineer #1657.