Doesn't matter where the animation comes from, it's the fact that jitter isn't noticeable anymore using Noesis. HOWEVER, Noesis isn't what I'd call 'ready' for use with JKA. Still a few bugs, but hopefully they will get sorted by Rich.
But in the "jittery bones" thread you stated the dotXSI files played fine in ModTool... so jog my memory-- is this jitter present in the official, original _humanoid.gla file???