Why does Apple Internet Accounts request more permissions to Exchange than the Outlook app?

My IT department has started blocking access to our Office 365 Exchange server. They say it is because when authenticating with Apple Internet Accounts, the app requests more access than it needs - more than what the Outlook app requests. Is this true, and if so, why? Because of this, we are no longer able to use Apple Mail and Calendar to connect to our work accounts, and they may also shutdown access from iOS.