Why is the screensize in the editor greater than 1?

According to the documentation, we are supposed to give values between 1 and 0 for the LOD level transition.

However, the mesh editor shows values far greater than 1. I include a pic here where the screensize of my model is given as greater than 7!

How am I supposed to determine the correct screensize between 1 and 0 for the LOD settings, when the editor gives a misleading value. Is this a bug?