I'm not totally sure, but I think it might make sense that all heatbeds with glass on top will measure in similar way.

I think the thermistor being sandwiched between kapton tape, the bed, and some sort of insulating material creates a very small air gap that holds its heat in much better than the surface of the bed which is open to the environment. I wouldn't be surprised if the thermistor is measuring the correct temp for its location underneath even though this isn't a very exact measurement for the surface of the glass.