Filters/slicers over calculated (average) values in line chart

Hi all,

Great community, I was able to find almost all solutions and answers to the questions I've had.

But the one remains whcih I am struggling to deal with.

I have a simple table like below

Multiple regions, countries and location types.

3 reports for, let's say 3 years 2016, 2017, 2018 (Report column), 

12 reporting periods/months (P01-P12)

for each year (report) and period (R.Period) we may have several lines with values (Value) for same location (Region, Country and type)

Last column (RunningTotal) is a calcualted value, which uses a pivot calculation (total value for speicifioc year, period and location) all calculation are processed in Excel which is lated sourced by PowerBI.

In Excel I have been using a pivot chart with slicers to show 3 lines for 3 years by period (month)

Slicers were controlling Region, Country and Type. 

For the value I have been using an 'AVERAGE' from RunningTotal

Worked brilliant.

Now I am trying to achieve the same in PowerBI.

So, I have created a line chart visual with R.Period in Axis, Report (year) in legend and  RunningTotal as a value.

By default it showed the SUM, so I have changed the RunningTotal setting to 'AVERAGE'

Brilliant, It worked I thought....

BUT when I have added 3 slicers for Region, Type and Country I have realized that they are NOT working (as they did in Excel)

After digging I have found this:

https://community.powerbi.com/t5/Community-Knowledge-Base/Calculated-Column-Table-Change-Dynamically-According-to-Slicer/ta-p/163321

I have tried to find a suitable workaround but failed.

I do not need a matrix table, I need a line chart as shown above with Running total, which could be controlled/filtered  by slicers/filters....

Any advice?
THANK YOU

UPDATE: In fact I have realized that my source table looks different from the example shown above.
'Running total' is calculated in Excel for specific 'Report' (Year) and R.Period ONLY. 

But while there is a Pivottable behind the RunningTotal (as shown above), the source table was recalculating the RunningTotal values when slicer filters were applied (e.g. selecting specific region or country only - recalculates the values in pivottable > values in the table column 'RunningTotal' were recalculated as well and LineChart was updated as well).

So in reality, file sourced to PBI looks like below (no filters applied)

I guess I will need to update the RunningTotal calculation logic in the source file....
Or make the proper RunningTotal calculation within PowerBI - 

Any advice how to achieve it and get to the Linechart as shown above?