I have faced the same situation and this is what I have done. On QV11, chart properties, there is a new tab called "Dimension Limits": here you can limit the number of elements. The tricky detail is that what you will choose here will be applied only at the values of your first enabled expression.
So, in your example, go in that tab and select "Show Only" "Largest" "13". Now go on the expression tab and add (AS FIRST EXPRESSION FROM THE TOP): max(date(dev_finish_date))
The idea is to have the date value for every point in your char, the Dimension Limits will display only the latest 13 weeks. If the formula is not working correctly try to play around the idea.
The expression must to be "Enable" and "Invisible"; all the rest must to be unselected otherwise the graph will be modified. The expression is used only as filter.