Rolling Sum for Dax Measure

[balreenBDO]

Hi,

I have the below formulas:

EOY Comparative =

Var selectionMonth = SELECTEDVALUE('Calendar Date To'[FiscalMonthName])

Var selectionMonthNumber = SWITCH(UPPER(selectionMonth), "JAN", 1, "FEB", 2, "MAR", 3, "APR", 4, "MAY", 5, "JUN", 6, "JUL", 7, "AUG", 8, "SEP", 9, "OCT", 10, "NOV", 11, "DEC", 12, BLANK())

Var selectionYear = IF (selectionMonthNumber >=7,

                    YEAR(SELECTEDVALUE('Calendar Date To'[Fiscal Year]))-1,

                    YEAR(SELECTEDVALUE('Calendar Date To'[Fiscal Year])))

Var slicerYYMM = selectionYear& "-" & Format(selectionMonthNumber,"00")

var selYear = Max(RawData[FP])

Var Outcome = CALCULATE(IF(

        DATEVALUE(selYear) <= DATEVALUE(SlicerYYMM),

        [SumAct Formatted MTD],

        [EOY Month Value]

    ), YEAR('Calendar'[Fiscal Year]) = YEAR(SELECTEDVALUE('Calendar Date To'[Fiscal Year])))

Return

    Outcome

EOY Month Value = ([YTD SUM EOY])/ ([EOY Cummalative Days] - [EOY Number of Days in Month]) * [EOY Number of Days in Month]

YTD SUM EOY =

Var selectionMonth = SELECTEDVALUE('Calendar Date To'[FiscalMonthName])

Var selectionMonthNumber = SWITCH(UPPER(selectionMonth), "JAN", 1, "FEB", 2, "MAR", 3, "APR", 4, "MAY", 5, "JUN", 6, "JUL", 7, "AUG", 8, "SEP", 9, "OCT", 10, "NOV", 11, "DEC", 12, BLANK())

Var selectionYear = IF (selectionMonthNumber >=7,

                    YEAR(SELECTEDVALUE('Calendar Date To'[Fiscal Year]))-1,

                    YEAR(SELECTEDVALUE('Calendar Date To'[Fiscal Year])))

Var slicerYYMM = selectionYear& "-" & Format(selectionMonthNumber,"00")

Return

CALCULATE([SumAct Formatted MTD], ALL('Calendar'[Date]), 'Calendar'[Date] >= DATEVALUE(slicerYYMM) && 'Calendar'[Date]<= DATEVALUE(slicerYYMM))

Slicers
Month Name	July
Fiscal Year	2022
No of Days	31	31	30	31	30	31	31	28	31	30	31	30
Rolling Days Sum	31	62	92	123	153	184	215	243	274	304	335	365
	Actual	Forecast	Forecast	Forecast	Forecast	Forecast	Forecast	Forecast	Forecast	Forecast	Forecast	Forecast
	July	August	September	October	November	December	January	February	March	April	May	June
Amount	100	100	96.774194	100	96.77419	100	100	90.3226	100	96.77419	100	96.77419

The highlighted in brown is my expected output. My actual values return as expected but I am not aware on how to consider the rolling forecast values in the EOY Months Value formula. 

Examples for output:

September should take the YTD sum (only July due to slicer selection) and take its previous EOY months value August to calculate its own value. 

October should take the YTD sum (only July due to slicer selection) and take its previous EOY months value August and September to calculate its own value. 

Hope this explains the issue in getting the rolling sum for EOY months value

Thanks,

Balreen