From a European perspective a 15-22 minute dwell time sounds ludicrous. My local train station is pretty large and designed around through trains, and a 7-minute followup between departures (so between train 1 departing on track X to train 2 departing on track X) is routine here.
If it can be done over here, what makes Penn Station so special that they need 3x as much time? Why can't Amtrak do what other railway companies have been doing for years? Amtrak is already lying about other countries using headway-based scheduling, so can they really be trusted about the rest?
I have no idea if this ETA article is 100% trustworthy, but Amtrak definitely isn't.