So I think he problem you are having here, is that you are using the date as a DATEPART and not a DATETRUNC (in the date options the top set are DATEPART, so months, and the second set are DATETRUNC so month year). I'm not sure how you've calculated your rolling, so I've done this here and used as a filter. I've also filtered the data, as the superstore data set I have goes to 31/12/13...so wouldn't demonstrate the point very well, being the only month where your current version works!
Using the Date at Month level they are now plotted in the correct order. If you want the axis to just have the month, you can set this as a display as in the formatting for the date.
Hope this is what you wanted...and makes sense, please post back if not
Rolling 12 Month.twbx 340.6 KB