Filtering Sales with Dates

Hi Tob_P 
It was a bit confusing as TP2 Posting date is 12/06/2020 which is before the very first date in the sample sales table. See below screenshot. However, I believe the proposed solution is workable but I have serious doubts about the performance. Please refer to attached sample file amended with the solution.

Total Sales On and After = 
SUMX (
    GENERATE ( 
        'Nav_Item Ledger Entry',
        CALCULATETABLE ( VALUES ( 'Nav_Stand Items'[Item No_] ) )
    ),
    VAR PostingDate = 'Nav_Item Ledger Entry'[Posting Date]
    VAR CurrentItem = 'Nav_Stand Items'[Item No_]
    VAR CurrentCustomerSales = CALCULATETABLE ( 'Nav_Sales History Master' )
    VAR FilteredSalesTable = 
        FILTER ( 
            CurrentCustomerSales,
            'Nav_Sales History Master'[Item No] = CurrentItem
                && 'Nav_Sales History Master'[Posting Date] >= PostingDate
        )
    RETURN
        SUMX ( FilteredSalesTable, 'Nav_Sales History Master'[Sales] )
)