I'm confused, if in the 1 - 2 weeks the cell voltage went from 4.20 volts to 3.8 volts, I would check to make sure that the battery is ok as it probably is not. Now if you are worried about the batteries cells differing from 3.80 volt to 3.81 volts while in storage mode for the 1 - 2 weeks that is fine, mine do that all the time.