Sorry for posting the question using layman's terms. The FlightTracker display in the cabin shows MPH and KPH so that's how I posed the query.
I still think its kinda funny to take 580 steps forward and 200 back. But I look forward to experiencing Mach 1 (in a way) on the way back.
Enjoy the classic tale I found a while ago that I think y'all will enjoy, whether knots or MPH, IAS or TAS.