[css-images-4] more tweaking

Author: tabatkins

css-images-4/Overview.bs

@@ -1981,9 +1981,9 @@ Setting The Viewbox: the 'object-view-box' property {#the-object-view-box}
 			When the element is painted,
 			its contents are scaled and translated
 			such that the element's contents
-			retain the same position and size
-			relative to the view box's final size and position
-			that they had when the view box's dimensions were first determined.
+			retain the same position and size,
+			relative to the view box's final size and position,
+			that they had when the view box was determined (above).
 
 			Issue: Have not yet defined what happens if the view box is zero-area.
 			It's an error case,