Gold differences graphs are incorrect with "negative gold" (minor spoilers from semi-finals)

Throughout the LCS Riot has been showing gold differences graphs as a game has gone on. This is fantastic and great! I really like seeing information such as this. The only problem is that there is a simple inaccuracy in how it's shown.

http://i.imgur.com/tgnHoWH.png

The above is a gold graph that comes from a recent semi-finals game showing clearly that the difference is "negative gold." Above the X axis (when blue has more gold) it's positive and one might think normally that below the X axis is a negative value but this graph is showing a difference between the two teams. The difference is a positive value, regardless of which team has more gold. It's a little thing yes but it's a simple mistake that can be easily fixed.