Tricky Rolling 6 months Average

i am trying to work out the rolling 6 month average value (unable to provide data) Sorry. In the screen image below i am getting the same result as the Result Column the result i am expecting the Rolling 6 month column is the average of 19256220 + 18997872 = 1917046 for the month of FEB 2019 which is worng 

Sample Data Based on Screen image

https://www.dropbox.com/s/9pi81bv5acjswfg/FADSampleData.pbix?dl=0 

My measure is

Rolling 6 month =

VAR _ selcteddate = Calculate(selectedvalue(Llo_Data[Date]))

VAR _Result =
IF(Not(
Llo_Data[Alloc in month] = 0) && Not(Isblank(Llo_Data[Alloc in month])),
Calculate(Averagex(Llo_Data,[Result]),
Filter(
Llo_Data,
Llo_Data[Date] >= DateaddLlo_Data[Date],-6,MONTH) &&
Llo_Data[Date] <= -Selecteddate
Return

_Result