It's not really about trust but more a difference in methodology. Normally any tour gross is similar to the attendance times the average ticket price. This is clearly, indisputably not the case with Katy's US grosses. So they are adding something that other promoters don't add. And we'll probably never know what that is.
It does mean that there's simply no way to fairly compare her tour grosses to anyone else's. It was already an issue when some artists included festivals and charity events in their total gross. But this is an even larger discrepancy.
Oh I don't deny that the average ticket price shows that they're adding in other things. I just don't see why that's such a big deal though. Her VIP tickets are just for seats for her concerts. It's not like she's selling tickets for meet and greets and including those.
I don't know why people spend so much time comparing this stuff anyway tbh.