'Deleted apps and users' using data every month even though I only add/delete apps on WiFi.

[Missy Uneek]

I find it suspicious that it's always close to the same amount of MB supposedly used, month after month. How likely is that?!
Many answers here say it's data used from an app that was removed, or an account change. Maybe that's the case for some people but I only add/delete over WiFi. Even if every month I was mistaken and forgot something I did, the amounts should vary.
I hope someone here can tell me
*How can I find the full details of activities, including the sneaky ones?
I admit I'm at the equivalent of a grade schooler at all of this. I'm not even sure how much I don't know.
I'm going to test it again next month, being careful to record every action. I will give an update with the results.
Btw this phone is a Moto g5 plus. I haven't had it long. No offense to the Moto but I miss my Samsung S6. I had finally gotten to know it when I dropped it and the screen shattered

 

[B. Diddy]

I'm not sure how long the system keeps the record of how much pooled data the deleted apps used before they were uninstalled. I would have thought it was maybe a month or two, but maybe Moto keeps track of it for longer than that. It doesn't mean that previously uninstalled apps are still actively using data, though.

I'm not sure what you mean that you only add/delete over wi-fi. Do you mean that you only use wi-fi on your phone, without any mobile data usage at all?

 

[ManiacJoe]

The "data used" is not the data transferred during the download and install.
The "data used" is the data that the app sent and received between being installed and uninstalled, for that billing month.

To see what data amounts are being used while the app is installed, take a look at the info in your Settings app.
On my Android 8 LG phone, it is at Settings > network > data manager.
You should be able to see both the wifi and mobile data amounts.