The SVS corrects the input voltage in increments (taps). If the input voltage moves form one tap to another, the output voltage can move visibly  but remain within the output parameters of the unit. For example, as per table, if the input voltage is 240V, output is 240V. If the input moves up to 245, the output moves to 218. The LED display will remain unchanged in this instance as the output is still within the parameters (6% accuracy).