does jaS mean "differently (from the norm)", or "differently (in contrast with something I just said)"? Maybe both?
I'm pretty sure this is a deictic issue: that is, jaS is used in relation to whatever you're talking about. If you're talking about the norm, that's what jaS is referring to. If you're talking about something else you just said, that's what jaS is referring to. However, I don't think Okrand has ever used it or jaSHa' is a sentence, so I can't supply any evidence.