I purchased a Ego VV (3.2v~3.7v~4.2v) passthru 650mAh from a Chinese vendor, according to their info page the voltage settings should be stabled when usb connected. I'm having trouble to understand their description of use if it means that it requires 5 clicks to switch desired voltage for each puff or should it remain the same voltage until I reset? I got the model with retractable usb cord and I couldn't manage to keep the higher voltage settings for more than 5 minutes, it constantly reversed back to the default (3.2v). Is this a defected product or my misunderstanding as to how vv battery works???