Apparently, you can bait it by letting them mash out an S and then punishing. I don’t know myself, since I rarely go for Exchange to begin with. I still haven’t gotten the hang of including it in my team set-ups.
It definitely doesn’t seem anywhere near a 95% counter rate for me. Against good players, I get much more consistent counter rates by figuring out their tendencies and teching accordingly. Since D+S gives a full meter and B/F+S gives half a meter, it’s a pretty straightforward mindgame. I only do the spinny mash thing against random scrubs online.
Down Exhange builds a full super bar instantly, plus the bar gained from the rest of the combo. Back/Forward Exchange is half a bar.
Also, there are only 4 ways to tag. DHCs and alpha counters both cost meter, and raw tags are hella risky. Exchange is very low-risk (it resets the situation to neutral) and actually builds bar.