I'm almost wondering if perhaps you're interpreting moving from the peak of the experience to that more stimulated and less magical bit at the end where you are still 'rolling' per se, but most people are starting to feel down. I've had tested molly that had us rolling for quite some time, I'd say 5 hours overall after redose. A friend of ours began complaining that he was 'down' when he was still very clearly under the effects. Really, he was just no longer rolling face, because the peak can end rather suddenly sometimes. Just an observation. Double-dropping most certainly should last longer than 3 hours, which is in my experience the length that people spend where everyone is "OMG ROLLING FAAAAAAAACE YOUR HAIR IS SO SOFTTTT" and after that it settles down into some pretty regular high-kid talk for a couple hours after that, then residual stimulation for quite some time as the comedown unfolds.
This is only in my experience.