K50    =SumCellsByColor(K8:K48;$B$4)
K52    =СУММ(K8:K48)-K50

Function SumProductCellsByColor(rData As Range, rData2 As Range, cellRefColor As Range)
    Dim indRefColor As Long
    Dim cellCurrent As Range
    Dim sumRes
    Dim i&
 
    Application.Volatile
    sumRes = 0
    indRefColor = cellRefColor.Cells(1, 1).Interior.Color
    For Each cellCurrent In rData
    i = i + 1
        If indRefColor = cellCurrent.Interior.Color Then
            sumRes = WorksheetFunction.Sum(cellCurrent * rData2(i), sumRes)
        End If
    Next cellCurrent
 
    SumProductCellsByColor = sumRes
End Function