Weird ''Who's online'' statistics?

[Nesa]

We all know that on IPS3 default time for this statistics was 15 minutes. On my forum, in prime time (between 8 and 10 pm), these statistics showed eg. 45 Members, 5 Anonymous, 150 Guests. These numbers were common.
With the arrival of IPS4, we all know that this time increased to 30 minutes, and that we can not so easy to change it. I do not mind increasing the time interval from 15 to 30 minutes. Everything is ok. It would be logical to expect that number of users online increase to some extent. The time frame was increased from 15 to 30 minutes and it would be logical that to increase the number of users online.
 

Indeed, the logic proved correct in practice. After switching from 3.4.5 to 4.1.8, this statistic in prime time (between 8 and 10 pm), showing, for example, 85 Members, 9 Anonymous, 210 Guests. Basically, the total number of users online was 300, up to 350.
Then, a few months ago I did the upgrade to IPS 4.1.9 from 4.1.8. Since then, the statistics show nonsense. Now I'm on version 4.1.12.3, and this statistic still shows stupidity. For example:

6.30.2016. 8:07 pm
38 Members, 5 Anonymous, 47 Guests

6.30.2016. 8:14 pm
34 Members, 5 Anonymous, 55 Guests

6.30.2016. 8:31 pm
30 Members, 2 Anonymous, 59 Guests

6.30.2016. 8:54 pm
24 Members, 2 Anonymous, 62 Guests

Not even 100 users online.
 

Maybe someone will think that there might be a real decline in the number of visits. But, Google Analytics show that my forum, in the period from 5.30.2016. to 6.29.2016. has more visitors and more sessions than in the same period last year (+9.3% sessions, and +19% in  the number of users). To make it more interesting, for example in 4am (when everyone is sleeping), ''who's online'' IPS statistic shows for example 6 Members, 1 Anonymous, 41 Guests on my Forum. How is it possible that the number of online Guests in 4am is almost the same as in primetime??? 

Did anyone else notice the strange, weird results that ''who's online'' block is showing?

 

 

[Nesa]

I just found, March 2016, IPS 4.1.8, afternoon (14:31):

37 Members, 2 Anonymous, 123 Guests.
Since switching to 4.1.9 I have not seen more than 100 Guests online ever ... and this was in the early afternoon, not in prime time.

[marklcfc]

It's actually 24 minutes and after I upgraded on Tuesday from 3.4 my online stats 300-400 down on what it used to show. I used to have mine at 30 minutes but that's a huge drop.

[Nesa]

@marklcfc

On 21.7.2016. at 7:37 PM, marklcfc said:

It's actually 24 minutes

Yes, I thought it was 24 minutes, but here's an example from a few moments ago:

My forum, 01:20 AM
As you can see, there are users over 24 minutes. Check on your forum.