Xbox PC Rog C37 Slow Speed Control Speeds Are Wrong!

I thought that I would use the Slow speed control when coupling up to a train, and noticed that the loco speed doesn't match the selected speed setting.
0.5mph is running at 0.8 to 1mph, 1mph is running at 1.5 to 1.7mph, 2.7mph is running at 4.4 to 4.6mph

I know it's only a minor bug. But it's so annoying! Especially as it works great on the TV's 37