User Profile

For an app in a given timeframe, Appstore Connect reports 1.100 downloads on the first click on "Analytics". (and also after that, I just want to emphasise that this is the "main" number shown for downloads and re-downloads combined) Since our users have to register, we have a clear metric - we have 1.600 registrations for the same timeframe. The short question: Where are the other 500? To me the docs are not clear, from which point does a user have to have opted in to analytics data, can they also opt out of the main "download" metric? If yes, the answer is that, but it looks like the privacy only starts somewhere down the road, in usage statistics...