interfaceHeight: Improved the description

etc/caseDicts/postProcessing/probes/interfaceHeight

@@ -7,9 +7,11 @@
 -------------------------------------------------------------------------------
 Description
     Reports the height of the interface above a set of locations. For each
-    location, it writes the distance from the boundary to the interface,
-    intersecting the location. It uses an integral approach, which computes an
-    average where for multiple interfaces above or below a location.
+    location, it writes the vertical distance of the interface above both the
+    location and the lowest boundary. It also writes the point on the interface
+    from which these heights are computed. It uses an integral approach, so if
+    there are multiple interfaces above or below a location then this method
+    will generate average values.
 
 \*---------------------------------------------------------------------------*/
 

src/functionObjects/field/interfaceHeight/interfaceHeight.H

@@ -26,10 +26,11 @@ Class
 
 Description
     This function object reports the height of the interface above a set of
-    locations. It writes the height above the location, above the boundary,
-    and the point on the interface. It uses an integral approach, so if there
-    are multiple interfaces above or below a location, this method will return
-    an average height.
+    locations. For each location, it writes the vertical distance of the
+    interface above both the location and the lowest boundary. It also writes
+    the point on the interface from which these heights are computed. It uses
+    an integral approach, so if there are multiple interfaces above or below a
+    location then this method will generate average values.
 
     Example of function object specification:
     \verbatim