Reverse Running Total for Forecast with condition - Dax Help

[RENJITH_R_S]

Hello friends,
can you help me to get a dax formula to get reverse running total of forecast

see my sample data
Gap = Planned - Actuals

how reverse running total is calculated is

if acutals for current month is present
then it took Reverse Running Total planned - Actuals + Gap, Here 27-1+1 = 27

if Actuals is not present the prev month RRT forecast- current month planned
example in jun no actuals the may forecast value - june planned value , 27 - 3 = 24

Month	Planned	Reverse Running Total planned	Actuals	Gap	Reverse Running Total Forecast
May-24	2	27	1	1	27
Jun-24	3	25			24
Jul-24	4	22			20
Aug-24	5	18			15
Sep-24	6	13			9
Oct-24	7	7			2
Total	27

[Greg_Deckler · Accepted solution]

@RENJITH_R_S Try:

Column = 
    VAR __Month = [Month]
    VAR __Actuals = SUMX( FILTER( 'Table', [Month] <= __Month && [Actuals] <> BLANK() ), [Actuals] )
    VAR __Gap = SUMX( FILTER( 'Table', [Month] <= __Month && [Actuals] <> BLANK() ), [Gap] )
    VAR __Planned = SUMX( FILTER( 'Table', [Month] <= __Month && [Actuals] = BLANK() ), [Planned] )
    VAR __MinMonth = MINX( 'Table', [Month])
    VAR __Start = SUMX( FILTER( 'Table', [Month] = __MinMonth ), [Reverse Running Total planned] )
    VAR __Result = __Start - __Actuals + __Gap - __Planned
RETURN
    __Result

[RENJITH_R_S]

Thanks @Greg_Deckler