Power flow through a waveport

Hello,
I am trying to understand the field calculator.
I have found the cookbook explaining how to calculate the power flow through a surface. But something doesn't seems right (or that i just don't understand something...) - if i'm using it on a surface which is a 1W waveport, shouldn't the integral on the entire surface show 1W?
Thanks!

Ya it should show 1W

Akr

This is a question for Ansoft. It would not surprise me if the power flow is reduced by the reflection loss.