Calculate temperature of area by point temperature
 

I have a horizontal pipe and would like to know what is the average temperature in an intersection.
So I selcted the points of this intersection, and via filters -> integrate variables I can see the selected points and their temperature.
But just calculating now the average would not be correct since there is yet no connection to their coordinates, area they are representing.

Is there a possibility to do exactly this, since paraView knows as well the coordinates?

Another (smaller) issue I have is that if I try to export the spreadsheet is the number of digits exported. ParaView is showing me 12 digits (as I configurated in OpenFoam), but the exported .csv has only 6. Is it possible to change the number of exported digits?