Repeatability with multiple Allegro A1326LUA-T analog hall sensors

Hi,

I'm trying to make a couple of magnet strength testers using Allegro A1326LUA-T hall sensors. The issue I have is I can't seen to get the same Gauss readings with the different hall sensors. I'm reading a cylindrical magnet mid-length (reading largest of North and South Pole).

ie. with everything the same but a different hall sensor, I get 792 Gauss on one and 873 Gauss on another just by swapping the sensor. I zero the Gauss reading on startup and locked down the spacing, location, and everything else, only difference is the sensor.

The code is the same as this: Arduino Playground - Hall Effect

Is there a calibration mapping required for each hall sensor or something. Any help on this?

Thanks!