[Al Skierkiewicz]

Guys,
I think you are documenting the interaction of a few different elements in the way you are making your measurements. You first have the brush spacing/segment frequency to deal with. Then you have the inductance of the motor vs. the switching frequency of the Jaguar. And finally you have the sample rate of the current monitor in the Jaguar.
It is well documented that the higher switching frequency of the Jaguar does limit current at lower PWM values in higher power motors. This is due to the finite rise time of the applied pulse interacting with the motor internal inductance. It is one of the things that make the Jaguar seem more linear than Victors. Obviously this much more pronounced with CIM motors and FP than with the window motors or the Banebots. At small pulse widths and large inductances, the voltage at the motor terminals never reaches the supply voltage.
If the sample rate or time are sufficiently long enough, at lower RPMs, you will undoubtedly read the current through two windings (while the brush covers two segments) causing a higher reading. As the motor achieves higher RPM, the sample rate likely moves to a point where most current is read while the brush is on only one segment and therefore lower.
There is likely to be significant interaction between the current pulse sampled by the series resistor in the Jaguar and ADC used to transmit the current back to the CAN bus.
My suspicion on the Ryobi drill motor curve is likely due to hysteresis in the core of the motor at lower pulse widths and it's design for increased torque at a specific RPM.
BTW, we should also take into account the rather strange, very short, voltage spikes that occur with Jaguars at the pulse edges under certain conditions. These vary with motors and speed.