Hall sensor unipolar switch digital

Hi guys. I just bought a Hall sensor Allegro A1302, it’s a proportional bipolar analogic sensor. But I need an unipolar digital switch. With the sensor I have, I measured the magnetic field/signal. These are some plots of the signal:

I searched in ebay the unipolar sensors and the only one I found is this one:
In the documentation that I found, this is the function of the sensor

Then there are the on/off points, but why they are double, max and min!?!?

Please, can someone help me choose the sensor I need.

P.S. Excuse my bad English.