Ammeter Battery overcharge

I have the MP elec ignition so no points. Is my current VR ( see pic) a points style? Its the same one since Dad bought the car in 2012.
So it doesn't make sense? Car has been super reliable with very few issues. Also new M&H engine forward harness. Takes up 2 of the 3 spots in bulkhead, so im assuming thats good.
I added an extra ground wire from reg mount bolt directly to battery -ve ( see pics) I also got dremel out and ground paint off mount holes.

With car idling I have 12.93 directly off battery posts.
At idle and from battery -ve to VR case I have 8 mV.
At 2500 rpm battery -ve to VR case 17mV.

Any help appreciated
Thanks
Steve