FYI holding the left button shows the battery voltage, not the output voltage. You need to get a meter in between the vamo and the atty to read the output voltage.
(Actually, before you try to figure that out, you also need a meter or scope that can read PWM to get a vaguely accurate reading.)
(Actually, before you try to figure that out, you also need a meter or scope that can read PWM to get a vaguely accurate reading.)