If the AVR does not have the optional 3 (Position measurement), will it switch the tap automatically according to the load voltage level?

The AVR performs regulation in automatic mode, independent of the optional TAP Position Measurement, through the up and down output relays.
Without the TAP's measurement position, it is not manageable to give manual commands directly into the equipment to raise or lower the voltage. Without this function, can not be ascertained if the tap changer is already at the extremes (maximum or minimum TAP) or if the tap changer was successful.