Shifting ability scores

<blockquote style="margin: 0px 0px 0px 40px; border: none; padding: 0px"><i>Players now can modify their ability scores by subtracting points from one ability and adding them to the other ability in that pair. No more than 10 points can be shifted in this way.</i></blockquote><i><br /></i><div>Does this mean no more than 10 points among all ability pairs, or can you shift up to 10 points in each pair?</div>