Quote Originally Posted by MrCookTM View Post
Because that's the proper way to do it, as using duality on your next armor crush is a dps increase over holding it for your AE, unless you would AE combo right after AC (aka you don't have to mutilate/SF because they're still running and don't fall of soon), in which case holding it a few seconds for AE is worth it. Shasta's guide has the math for this, if your interested.
Since this disagrees with the math I posted earlier, I looked up Shasta's NIN guide. Neither his reddit post nor his forum guide go into the math beyond "don't delay it so long that you lose a chance to use it later." The math I did earlier says that it's fine to do AC->SF->MU->DualityAE, because that's still a pps increase over using it for AC (just barely). Until someone points out a flaw in my math, anyway...