My bad.. 150 deg is extremely cool ,my car has never run 150 deg at operating temp in my 33 years of ownership. The norm is 165 to 185 deg. Still your coolant system is the bomb..
I have it the other way around. My VDO gauge is showing like 185° sitting idle with the AC on and the scanmaster is showing 215°+. I have a cold case aluminum rad with dual fans and a box in kit. I changed the gauge sensor at one time but I think the ECM one is original. Do they fail over time and show higher then normal readings?