When using blow-out pipettes the last drops in the tip of the pipette must be dispensed, as well. To do so the small blow-out bellows should be pressed once as soon as the meniscus in the pipette tip comes to a standstill.
If other pipette types are used, the residue has to remain in the pipette tip to have the correct volume dispensed. The blow-out bellows should then only be used to blow out residual liquid after the work is done.