How to map website's user login session with Adobe Analytics visits/instance using DTM?

Hi,

I am tracking user name while logging in to the site.
I am using an eVar to store it once logged in and I have selected to remember its value for Visitor level in Dynamic Tag Management.

Now I am confused when seeing report what to consider as "no of logins" - Instance or Visits.
Both seem to show incorrect values.

I want to know how many times the user has logged in and the Avg Time Spent on the site.

Kindly help.