Volume isnt plotted in current value but rather the aggregate of the last 24 hours. We see a similar value in charting books based on more than just the current value. Charting books real time is helpful for active trading but it makes it more difficult to see the overall trends. We have now included a books/24 value which simply provides the average of the books over the last 24 hours and we set this as default. For users wishing to see realtime books instead, simply drop down the books menu and select real-time. This data is also availabel as a field from the field chooser and is how we relay combined order books in the mini-charts.