What is the logon.inc page in a per request policy good for (APM) ?

I was trying to do some customization of the per request page and noticed that nothing happened. Since I was not sure I did delete the complete content of that page leaving it empty. Result: no impact.

If I want something changed in the per request page, I have to do it on the session policy page. Is that expected behaviour ?

If yes... I was wondering... what is the usage of the logon.inc in a per request policy ?