Event module - which report is correct?


I have a singel session event. 

I want to take out all all contacts that are registered, but I don't know witch report to trust? 

Manage Attendees says its 79 contacts that have registered. Where some names are lost, why?

The form submission says that it is 93 contacts that have registerd, here I can see all the names.

And if I do a report in my CRM, based on Landing page ID, it says that it is 75 contacts.

What is correct and why is every page different? It does not give me much trust in the system.