Option Explicit

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim a           As Long
    Dim b As String, c As String, d As String, e As String
    Dim u           As Long: u = UsedRange.Rows.Count

    If Not Intersect(Target, Range("AR6:BC" & u)) Is Nothing Then
        a = Target.Row                ' строка, в которую вносим данные
        b = Range("BF" & a).Value     ' статус
        c = Range("BY" & a).Value     ' дата / время

        d = Range("BQ" & a).Value     ' статус
        e = Range("BM" & a).Value

        If b = "все заполнено" And c = "" Then Range("BY" & a) = Now
        If d = "все заполнено" And e <> "" Then Range("BZ" & a) = Now
    End If

End Sub