Lost customers

Unfortunately Amit, I tried it but unfortunately doesn't seem te work.

I am working with non-date periods. I have indexed the weeks, which start at week 1 in 2019 (index 1) and counting until today.

The rolling 3 and rolling 9 before 3 seem to give the correct result. However the Lost customer in period remain blank everywhere.

I copied the measures used below. Groepnaam is the customer name which is in the sales transaction table (hence customer/groepnaam is not unique in the table).

Hopefully you see what is missing.

#Rolling 3 = 

var MaxIndex = SELECTEDVALUE('FS_Vertaling weken naar perioden'[Index - week])
var MinIndex = MaxIndex - 12

return

calculate('03 FS measures'[Omzet totaal],
Filter (all('FS_Vertaling weken naar perioden'),
'FS_Vertaling weken naar perioden'[Index - week] <= MaxIndex &&
'FS_Vertaling weken naar perioden'[Index - week] > MinIndex))

#Rolling 9 before three = 
var MaxIndex = SELECTEDVALUE('FS_Vertaling weken naar perioden'[Index - week])-12
var MinIndex = MaxIndex - 52

return

calculate('03 FS measures'[Omzet totaal],
Filter (all('FS_Vertaling weken naar perioden'),
'FS_Vertaling weken naar perioden'[Index - week] <= MaxIndex &&
'FS_Vertaling weken naar perioden'[Index - week] > MinIndex))

#Lost Customer This Period = 
Sumx(VALUES(FS_Omzet_uren_all[Groepnaam]),  
if(ISBLANK([#Rolling 3]) && not(ISBLANK([#Rolling 9 before three])) , 1,BLANK()))