Cooling issue, but this time it's to cold...

Have some other things going on but, as I warmed the engine tonight for another issue I watched closely to the temps and had the radiator cap off to moniter. The engine warms pretty quickly, normal few minutes, very slow flow in the radiator from the bypass. As the gauge climbed to 170 ( keep in mind this is no driving, just sitting ) the water started to flow in the radiator. The temp after about fifteen minutes went to 190 and never got any hotter than that. The heater in the car had plenty of heat long before the stat opened. So from the start of this I was asking for help with why it cools to much while driving with airflow. All systems are operational and working correctly parked, but I can drive it all day and the gauge will barely if at all get to 120, and only if I get on it a little it will go to 150 but only till I start mild cruising, then cools right back down quick, if I just baby it around the gauge barely moves?????