Rice and Lavieh, you both have it correct actually. Generally speaking, there's not many situations (yet) that I feel it necessary to stance dance, but when I do, it's absolutely right for the situation. The movement heavy mini-phase of Ravana Ex and A3's add phase are prime examples. Yes, I can do the A3 adds with it, but for pure speed of DPS on adds, Gauss off works perfectly well for me. And in Rav Ex, when running with tethers, I can still freely DPS while in motion.

All in all, it's situational. And while most situations don't necessarily call for Gauss NOT to be on, there are a few, and it's all about adapting on the fly.