Bad lambda calibration on M800.

[Polux RSV]

Both lambda sensors (LSU4.2) driven by M880 were previously calibrated using air calibration. During dyno session, lambda values showed lean and rich spot. But after changing the fuel table, there were no differences on lambda values. I even tried to double the fuel, but no difference.
At home I checked the sensors calibration, and the M880 showed about 1000 for each sensor. I tried to recal in free air, and values went to 1500 and 1300, which correspond to same setup on another motor.
Questions:
-Is it possible the calibration values changed? I imagine these values are stored in a separate memory, with TPS setup. They should not be affected with new tables dowloads.

- Knowing I ran the setup with 1000 instead of about 1300-1500, how to interpret the lambda reading I had ? i.e. was the motor running richer than the lambda values showed ? Leaner ?

Angelo