Still not ok. Dots should be 9. Your thermostat is not working. The one you have installed is faulty. Get it replaced again. Mine was doing the same and it got fixed after replacing the thermostat 4th time.
Also please look for any coolant leakages present. even a very small tiny leakage can cause this. If you are not sure about the leakage as a small leakage is not easily detectable because water evaporates before reaching the ground.
Pour a coolant of green color in your radiator and drive around for a day or two, then see, if there will be any leakage, there will be green marks present at the origin of leakage.
Happy Driving Man.