Use previous row in current column calculation

Hi mellon199 
Here is a sample file with the solution https://we.tl/t-KyxjUgcvAi

For a caclulated column:

Indexation Factor = 
VAR T1 = 
    FILTER ( 
        Data, 
        Data[Index] <= EARLIER ( Data[Index] ) 
    )
RETURN
    PRODUCTX ( 
        T1,
        1 + Data[Selected Index]
    )

For a measure:

Indexation Factor Measure = 
VAR SelectedIndex = 
    SELECTEDVALUE ( Data[Index] )
VAR T1 = 
    CALCULATETABLE ( 
        Data, 
        Data[Index] <= SelectedIndex,
        ALL ( Data[Selected Index] )
    )
RETURN
    PRODUCTX ( 
        T1,
        1 + Data[Selected Index]
    )