900 bed level points! Why?

Here is a good example of the reason that more mesh bed level points the first layer will be more perfect.

But the time for the bed level will be much longer with traditional probe sensor.

E.g. the time of 10*10 points is about 3 minutes, the time of 30*30 is about 30 minutes.

Fortunately, with BDsensor the time for the 30*30 points is only about 1 minutes.