I am no expert but with my limited understanding I think a 90 day last login period is a very useful marker to get an understanding of the current user base. What does seems detrimental to some degree is the fact that 300,000 active members have dropped to 57,000 even though there could be a whole array of reasons behind it. It certainly is not a good sign.
How did you define active, was it any member that logged in the previous 3/6/9 months?
If you hover over the little ? by active users, you can see it is 3 months. I can't remember if that's what I ran it as, but I don't think SM and IB would change it.