Weird alternator issues, This alternator is messing with me Options

[Downerman]

So, it came in the bundle of boxes (the alternator that is) when I bought the car and it appears to be a bosh unit . When I restored the car my logic was ,well I don't really know if the alternator is a newer unit with the regulator built in or not so what's the harm with putting a regulator on the main circuit board. I did and all was well. Sat at about 13.5V at idle and would go to about 14.5V at speed. So driving down the 101 highway I happened to look down at the voltage and it was pegged at 16. Pulled over and yanked the board mounted regulator. Fired the car back up and it was at 14 and then settled down to about 12.0V - 12.5V now where it will just stay.... at any RPM. When I turn the lights on it dips to about 11.0V - 11.5V.

Not enough I'm thinking so I put the old board mounted regulator back in. Fired it up and at idle it was 13.5V again. Ripped down the road a few miles and it @14.0V - 14.5V AGAIN. Then Pow.... pegged 16+ Put the lights on and 14.5V. Hit the brakes and @13.5V.

Drove home (just a few minutes) and at that idle with voltage saying 15V now I took my FLUKE and hit the battery. Spot on 15.0V so my gauge is true.

What the heck?? Anyone have any thoughts?