sameperiodTHISyear Time Filtering

The Why: So I am building out a visualization that leverages time as a filter/slicer to pick between two points in time. From that filtering/slicer of time I'm looking to see a like for like comparison between what would be most akin to the inverse of the 'SAMEPERIODLASTYEAR' function. 

The How: Basically, if I were to pick a date range between 8/1/2017 - 12/31/2017 or 8/1/2015 - 12/31/2015 I would want to have a series of values summed for 8/1/2017 - 12/31/2017 next to a series of values summed for 8/1/2018 - 12/31/2018. Or in the case of the second range, have the slicer tuned to 8/1/2015- 12/31/2015, and also have values summed (in a different location/visual) between 8/1/2018 - 8/1/2018. Basically, no matter the time change be it the year 2017, or 2015, or 2005 (if there were data), I'd want to see a measurement summation between the selected filtered date and the SAMEPERIODTHISYEAR. 

Note: The way I want to have the filter used in a way where the users pick the date value for the period in question, and in one chart they see the Selected Period's "burn rate" in one chart, then in a separate chart see the Current Year's "burn rate" in another chart. I've tried a few ways to work through this one, but with the variable of the calculation makes for DATEADD a little complex, because the Current Year is never going to be static during the timeline of the Power BI Report.