SUMX not working for variable table

Robert14358 , Split into two measures and try

AC Hrs (PW) =

VAR SSMAXDATE = [Date Selection (MAX) SS]
VAR MINDATE = [Date Selection (MIN)]
VAR SSPW = [Week Number (PW) SS]
return
SWITCH(TRUE(),
ISFILTERED(Date_Selection),
SWITCH(TRUE(),
CALCULATE(SUM(Fact_SNAPSHOT[SS_HRS_AC_Prev_Diff]),FILTER(ALL(Dim_Calendar),Dim_Calendar[Rolling Week #] <= MINDATE-1)) = [AC Hrs],
CALCULATE(SUM(Fact_SNAPSHOT[SS_HRS_AC_Prev_Diff]),FILTER(ALL(Dim_Calendar),Dim_Calendar[Rolling Week #] <= SSPW)),
CALCULATE(SUM(Fact_SNAPSHOT[SS_HRS_AC_Prev_Diff]),FILTER(ALL(Dim_Calendar),Dim_Calendar[Rolling Week #] <= MINDATE-1))
),
CALCULATE(SUM(Fact_SNAPSHOT[SS_HRS_AC_Prev_Diff]),FILTER(ALL(Dim_Calendar),Dim_Calendar[Rolling Week #] <= SSMAXDATE-1))
)


AC Hrs (PW) Sum = Sumx(SUMMARIZE(
Dim_ACT,
Dim_ACT[ACT_Key],
"_SUM",[AC Hrs (PW)] ),[_SUM])