The primary function of calibrating a laptop battery is not so much to condition it or minimize any memory effects that might occur (valuable as these effects may be), but to re-adjust the readout of the gradually diminishing charge of the battery to 100% when full and 0% when empty. This is necessary because the ‘100% charged’ value in particular is a moving target.
Apart from being drained when used, batteries gradually lose the ability to hold a charge. After a while you cannot recharge the battery to the original 100% anymore, because it can hold only (let’s say) 95%. Recalibration resets the extreme values to those measured when the battery stops charging (= 100%) and stops discharging (= 0%) during the calibration process. These 0% and 100% values may be affected by safety circuitry, but that doesn’t detract from this explanation.
