Paginated Reports Query

DEFINE
    VAR vFromDateTableStartofMonth1 =
        IF (
            PATHLENGTH ( @FromDateTableStartofMonth ) = 1,
            IF (
                @FromDateTableStartofMonth <> "",
                @FromDateTableStartofMonth,
                BLANK ()
            ),
            IF (
                PATHITEM (
                    @FromDateTableStartofMonth,
                    2
                ) <> "",
                PATHITEM (
                    @FromDateTableStartofMonth,
                    2
                ),
                BLANK ()
            )
        )
    VAR vFromDateTableStartofMonth1ALL =
        PATHLENGTH ( @FromDateTableStartofMonth ) > 1
            && PATHITEM (
                @FromDateTableStartofMonth,
                1,
                1
            ) < 1
    VAR vToDateTableStartofMonth1 =
        IF (
            PATHLENGTH ( @ToDateTableStartofMonth ) = 1,
            IF (
                @ToDateTableStartofMonth <> "",
                @ToDateTableStartofMonth,
                BLANK ()
            ),
            IF (
                PATHITEM (
                    @ToDateTableStartofMonth,
                    2
                ) <> "",
                PATHITEM (
                    @ToDateTableStartofMonth,
                    2
                ),
                BLANK ()
            )
        )
    VAR vToDateTableStartofMonth1ALL =
        PATHLENGTH ( @ToDateTableStartofMonth ) > 1
            && PATHITEM (
                @ToDateTableStartofMonth,
                1,
                1
            ) < 1

EVALUATE
SUMMARIZECOLUMNS (
    'ResultData'[Sample],
    'ResultData'[Date Sampled],
    'ResultData'[Sampling Point],
    'Analyte'[Analyte],
    'ResultData'[Class],
    'ResultData'[Result],
    'ResultData'[Status],
    'PRData'[PR],
    FILTER (
        VALUES ( 'DateTable'[Start of Month] ),
        (
            vFromDateTableStartofMonth1ALL
                || 'DateTable'[Start of Month]
                    >= DATEVALUE ( vFromDateTableStartofMonth1 )
                        + TIMEVALUE ( vFromDateTableStartofMonth1 )
        )
            && (
                vToDateTableStartofMonth1ALL
                    || 'DateTable'[Start of Month]
                        <= DATEVALUE ( vToDateTableStartofMonth1 )
                            + TIMEVALUE ( vToDateTableStartofMonth1 )
            )
    ),
    RSCUSTOMDAXFILTER (
        @SiteDEPT,
        EqualToCondition,
        [Site].[DEPT],
        String
    ),
    "TotalSamples", [TotalSamples]
)