Two questions about battery on ring 2

1) I get a different battery level reading on my windows computer app than I do on my Android phone app. Computer says 19% and the Phone says 39%. Why?2) I have had my ring doorbell for about 17 months. I have only charged it three times in that time. The last time was about two weeks ago. Not the battery is either 39% or 19% depending on what app to beleive. Which would tell me the battery is at the end of its cycle. Should I expect to only get less than two years out of the battery (3 charges)? Or are the apps screwed up and my doorbell is really more charged?