Samsung incall ui used by apps?

[JaMiHo]

Have seen a lot of questions about incall ui.
Its used when making/ending calls. If most of the answers are right.
But is it used by other apps like facebook messenger calls, whatsupp calls and alikes. Because my daughters bill does not show calls made at night, but incall ui is repetedly shown in myactivity.google..
Her ex is not welcomed in our house because off trouble with the law, that is an agreement we have, and she is aware im checking bills and activity because she is underaged. But promised her to not check her phone physicly....some privacy is right.
Phone: samsung galaxy S7

 

[chanchan05]

I'm not sure it is. Those apps have their own callui AFAIK.

 

[JaMiHo]

Ok....is there a possibility any other apps could use incall ui?
Because i cant get the notification in myactivity without making a call.
But i dont use messenger apps just regular calling an sms text.
For example the wakeup screen looks like a "call ending" screen, and the function is much the same...
Would like to be sure, i would not want to take the phone without facts to back up my claims.