Calculating the difference dynamically, based on Year selection

Hi, I am not sure if I understood your question correctly, but I tried to create a sample pbix file like below.

Please check the below picture and the attached pbix file.

I hope the below can provide some ideas on how to create a solution for your semantic model.

compare to the previous within the slicer selection: = 
VAR _currentselectsales =
    SUM ( Sales[Sales] )
VAR _currentselectyear =
    MAX ( 'Year'[Year] )
VAR _prevselectyear =
    MAXX (
        FILTER ( ALLSELECTED ( 'Year' ), 'Year'[Year] < _currentselectyear ),
        'Year'[Year]
    )
VAR _prevselectsales =
    CALCULATE ( SUM ( Sales[Sales] ), 'Year'[Year] = _prevselectyear )
RETURN
    IF ( NOT ISBLANK ( _prevselectsales ), _currentselectsales - _prevselectsales )

Jihwan_Kim  Perfect.

Perfect