Alternator - regulator mismatch?

The VR/ alternator is a sort of "servo loop." You feed battery power to the VR IGN terminal which in a Mopar is the "sensing" terminal. This is between the VR case and the IGN terminal

If the VR "sees" less than the setpoint, it ramps up field current which makes the magnetism in the rotor stronger, and this causes more output to be generated in the stator/ diodes. This then feeds out to the battery/ the VR IGN, and as that voltage comes up, the VR ramps back down. This all happens in a split second.

If you remove the cover from an original old style regulator you can see the contacts constantly pulling in and out. "Normally" you don't see this in the voltage of the system. That is because what is called the "inductance" of the alternator field slows down these cycles and sort of averages them out.