Discrepancies in Google Analytics user counts

Question

So I have two discrepancies in GA user counts that I am trying to understand.

The first is that my user count for a subset of the site's lifetime is greater than the entire sites lifetime.

Concretely: over the lifetime of the site it has had 872 users:

However, if we just look at the data after marketing dropped, we get 996 users, even though this is just a subset of the previous data.

How is this possible?

Secondly, the way I understand it, new users over the life time of the site should == users over the lifetime of the site, right?

Why then do I get only 720 new users over the lifetime of the site?

Answer 1

About Users calculation: https://support.google.com/analytics/answer/2992042?hl=en

But the most important is a part:

It relies on number of sessions and client-side time, so if a user's client-side time is incorrect, or if you are using a reporting view that filters out some sessions from a user (instead of all users), the data can be inconsistent.

So if you don't use "All Web Site Data" view, it is an answer. You see data calculated on the fly (sampled).

"New users" metric means: The number of users whose session on your property was marked as a first-time session

It's pre-calculated data, which is the nearest to real number of users (if you select whole site lifetime).