Well, there you go. Change back to the old ratio and log some data and then you'll be able to pinpoint what happened (though you have some info already). Little wonder it gets there quicker and with less Amps. Would be curious though to see the Amps at the old ratio. What you are doing is building a power/torque curve for the new motor. You just need some more points on the curve to define it better and see where you'd expect the max would be for both torque and power. Does your data logger record RPM?