For realz y0!
I always thought that what should happen is; When corrected normally, during a beat, if the sub starts with bumping outward, if they're reversed it would start bumping inward.
Well go try it yourself, doesn't harm your subs I presume, so don't hold me to it. But that's the first thing I checked, to see if the wires were on the right terminal, switched them, and I had much more bass...