Sameperiodlastyear funcion issue

Hi Darek

I do have a time dimension table generated by this Dax code:

Date =
VAR BASECALENDAR =
    CALENDAR ( DATE ( 2009, 01, 01 ), TODAY () )
RETURN
    GENERATE (
        BASECALENDAR,
        VAR BASEDATE = [DATE]
        VAR YEARDATE =
            YEAR ( BASEDATE )
        VAR MONTHNUMBER =
            MONTH ( BASEDATE )
        VAR MONTHNAME =
            FORMAT ( BASEDATE, "MMMM" )
        VAR YEARMONTHNAME =
            FORMAT ( BASEDATE, "MMM-YY" )
        VAR YEARMONTHNUMBER = ( YEARDATE * 12 + MONTHNUMBER ) - 1
        RETURN
            ROW (
                "DAY", BASEDATE,
                "YEAR", YEARDATE,
                "MONTH NUMBER", MONTHNUMBER,
                "MONTH", MONTHNAME,
                "YEAR MONTH NUMBER", YEARMONTHNUMBER,
                "YEAR MONTH", YEARMONTHNAME
            )
    )

the sales fact table is linked to this dimension by inv date = dim date