Rolling X months / X weeks calculations in DAX

I recently implemented rolling 12 month and rolling 6 week measures in a SSAS tabular cube for product registration counts. The rolling 12 month calculation is straight-forward and can be implemented using built-in DAX formulas. This implementation is based off of Alberto Ferrari's blog post. http://www.sqlbi.com/articles/rolling-12-months-average-in-dax/.