Bad Alternator? NO, BAD VOLTAGE REGULATOR

I've got my Dart "stored", up on jack stands, for the winter. While "stored" I start/run the vehicle for about 30-45 minutes (running through the gears (A904) putting about 2 1/2 miles on the odometer).

Yesterday I started/ran the vehicle as usual. While watching my volt gauge it never left the 10-12V range. Normally as the RPMs increase the volt gauge will increase up to the 12-14V range.

The battery is/was fully charged (battery tender in use) and was replaced in June (2014).

I did the AMP gauge bypass (MAD Electrical) several years ago. All connections are clean and tight.

The alternator has been on the vehicle as long as I've owned the car (~11 years).

What do you guys think?