Let's do this one step at a time.
I have created several calcs you'll need to do a rolling 12. I created a [beginning of range] and [end of range] calc that grabs 12 full months up to the last day of the previous month, based on the value of TODAY(). (You can adjust accordingly).
But I can't do any viz for you because you have no current data in your date set. As far as I can tell, it runs through some 2011 date. (Maybe that's a function of the extract packaged workbook creation.)
Values for start and end are displayed in your title.
I created a [Date range to display] calc that you will use as a filter. It will just bring in rows that fit the 12-month stretch. Since no current data is in the data set, I can't test it. But you would put that on your filter shelf and select for value = 1.
I created a [Rolling 12 to Display] calc that will give you a sort algorithm to sort the last 12 months properly. If you look at the sort selection on the MONTH pill in the columns shelf, you'll see how I used it.
I just pulled these from a rolling 12 viz I've done. It all works the way I needed it to.
Get some data for 2014 and 2015, put the [Date Range to Display] calc on the filter shelf (select for min and max value = 1), and I think you'll get your last 12 months.
Rolling Problem 2.twbx 86.5 KB
Get that to work, and we can take this logic to the next step you're looking to achieve.