WPF triggers or POCO INotifyPropertyChanged

WPF triggers or POCO INotifyPropertyChanged

I am making a WPF Datagrid with lots of related columns. When you change
X, Y should be X + Z. Etc. My first idea was to do this with POCOs and
INotifyPropertyChanged. But I see that this also can be done with WPF
triggers.
If I do the POCO there will be a problem with the first time initializing,
where you do not want these rules to execute. I guess I could come around
this by setting the private variables in a constructor.
The WPF trigger solution seems to be more complex and more difficult to test.
Any experiences would be appreciated